[Motorola Edge 40 Pro  / Moto X40 (China)] mudtub:
I'm also unable to update with lineageos updater (only been on official) Last few lines of updater log looks like this:

[0413/202134.327741] [INFO:snapshot.cpp(2588)] Mapped COW image for system_a at system_a-cow-img
[0413/202134.335841] [INFO:fs_mgr_dm_linear.cpp(250)] [libfs_mgr] Created logical partition system_a-src on device /dev/block/dm-12
[0413/202135.529287] [INFO:snapshot.cpp(2524)] Mapped system_a as snapshot device at /dev/block/dm-15
[0413/202135.532114] [INFO:snapshot.cpp(2557)] Successfully unmapped snapshot product_a
[0413/202135.536814] [INFO:fs_mgr_dm_linear.cpp(250)] [libfs_mgr] Created logical partition product_a-base on device /dev/block/dm-17
[0413/202135.553764] [INFO:snapshot.cpp(644)] Mapped product_a-cow-img to /dev/block/dm-20
[0413/202135.561048] [INFO:snapshot.cpp(2628)] Mapped COW device for product_a at /dev/block/dm-21
[0413/202135.567837] [INFO:fs_mgr_dm_linear.cpp(250)] [libfs_mgr] Created logical partition product_a-src on device /dev/block/dm-25
[0413/202137.967177] [INFO:snapshot.cpp(2524)] Mapped product_a as snapshot device at /dev/block/dm-27
[0413/202137.970407] [INFO:snapshot.cpp(2557)] Successfully unmapped snapshot system_dlkm_a
[0413/202137.994698] [INFO:fs_mgr_dm_linear.cpp(250)] [libfs_mgr] Created logical partition system_dlkm_a-base on device /dev/block/dm-31
[0413/202138.025389] [INFO:snapshot.cpp(644)] Mapped system_dlkm_a-cow-img to /dev/block/dm-32
[0413/202138.030187] [INFO:snapshot.cpp(2588)] Mapped COW image for system_dlkm_a at system_dlkm_a-cow-img
[0413/202138.058614] [INFO:fs_mgr_dm_linear.cpp(250)] [libfs_mgr] Created logical partition system_dlkm_a-src on device /dev/block/dm-37
[0413/202138.096633] [INFO:snapshot.cpp(2524)] Mapped system_dlkm_a as snapshot device at /dev/block/dm-39
[0413/202138.098752] [INFO:snapshot.cpp(2557)] Successfully unmapped snapshot vendor_dlkm_a
[0413/202138.124342] [INFO:fs_mgr_dm_linear.cpp(250)] [libfs_mgr] Created logical partition vendor_dlkm_a-base on device /dev/block/dm-40
[0413/202138.158485] [INFO:snapshot.cpp(644)] Mapped vendor_dlkm_a-cow-img to /dev/block/dm-41
[0413/202138.161651] [INFO:snapshot.cpp(2588)] Mapped COW image for vendor_dlkm_a at vendor_dlkm_a-cow-img
[0413/202138.189647] [INFO:fs_mgr_dm_linear.cpp(250)] [libfs_mgr] Created logical partition vendor_dlkm_a-src on device /dev/block/dm-42
[0413/202138.282881] [INFO:snapshot.cpp(2524)] Mapped vendor_dlkm_a as snapshot device at /dev/block/dm-43
[0413/202138.286879] [INFO:snapshot.cpp(2557)] Successfully unmapped snapshot system_ext_a
[0413/202138.295813] [INFO:fs_mgr_dm_linear.cpp(250)] [libfs_mgr] Created logical partition system_ext_a-base on device /dev/block/dm-44
[0413/202138.325222] [INFO:snapshot.cpp(644)] Mapped system_ext_a-cow-img to /dev/block/dm-45
[0413/202138.328053] [INFO:snapshot.cpp(2588)] Mapped COW image for system_ext_a at system_ext_a-cow-img
[0413/202138.351925] [INFO:fs_mgr_dm_linear.cpp(250)] [libfs_mgr] Created logical partition system_ext_a-src on device /dev/block/dm-46
[0413/202139.095553] [INFO:snapshot.cpp(2524)] Mapped system_ext_a as snapshot device at /dev/block/dm-47
[0413/202139.101493] [INFO:snapshot.cpp(2557)] Successfully unmapped snapshot vendor_a
[0413/202139.125375] [INFO:fs_mgr_dm_linear.cpp(250)] [libfs_mgr] Created logical partition vendor_a-base on device /dev/block/dm-48
[0413/202139.156123] [INFO:snapshot.cpp(644)] Mapped vendor_a-cow-img to /dev/block/dm-49
[0413/202139.159463] [INFO:snapshot.cpp(2588)] Mapped COW image for vendor_a at vendor_a-cow-img
[0413/202139.191486] [INFO:fs_mgr_dm_linear.cpp(250)] [libfs_mgr] Created logical partition vendor_a-src on device /dev/block/dm-50
[0413/202140.292847] [INFO:snapshot.cpp(2524)] Mapped vendor_a as snapshot device at /dev/block/dm-51
[0413/202140.296315] [INFO:snapshot.cpp(2773)] MapAllSnapshots succeeded.
[0413/202140.304154] [INFO:dynamic_partition_control_android.cc(351)] Loaded metadata from slot B in /dev/block/bootdevice/by-name/super
[0413/202140.305826] [INFO:dynamic_partition_control_android.cc(1232)] system_b is mapped on device mapper: /dev/block/dm-1
[0413/202140.307622] [INFO:postinstall_runner_action.cc(216)] /dev/block/dm-1 has been mounted R/W 3 times.
[0413/202140.309471] [INFO:postinstall_runner_action.cc(224)] Running backuptool scripts
[0413/202140.316320] [WARNING:utils.cc(625)] Unable to mount destination device /dev/block/mapper/system_a on /postinstall as ext4: I/O error (5)
[0413/202140.318128] [ERROR:utils.cc(629)] Unable to mount /dev/block/mapper/system_a with any supported type
[0413/202140.338271] [ERROR:postinstall_runner_action.cc(237)] Backuptool postinstall step failed. ret=32512
[0413/202140.339981] [INFO:utils.cc(644)] Not a mountpoint: /postinstall
[0413/202140.342650] [WARNING:utils.cc(625)] Unable to mount destination device /dev/block/mapper/system_a on /postinstall as ext4: I/O error (5)
[0413/202140.343985] [ERROR:utils.cc(629)] Unable to mount /dev/block/mapper/system_a with any supported type
[0413/202140.415717] [INFO:snapshot.cpp(2557)] Successfully unmapped snapshot system_a
[0413/202140.535651] [INFO:snapshot.cpp(2557)] Successfully unmapped snapshot product_a
[0413/202140.603587] [INFO:snapshot.cpp(2557)] Successfully unmapped snapshot system_dlkm_a
[0413/202140.675782] [INFO:snapshot.cpp(2557)] Successfully unmapped snapshot vendor_dlkm_a
[0413/202140.759872] [INFO:snapshot.cpp(2557)] Successfully unmapped snapshot system_ext_a
[0413/202140.847498] [INFO:snapshot.cpp(2557)] Successfully unmapped snapshot vendor_a
[0413/202140.857381] [INFO:snapshot.cpp(2801)] Shutdown snapuserd daemon
[0413/202140.960307] [INFO:postinstall_runner_action.cc(524)] Unmapped all partitions.
[0413/202140.966525] [ERROR:postinstall_runner_action.cc(532)] Postinstall action failed.
[0413/202140.975610] [INFO:action_processor.cc(116)] ActionProcessor: finished last action PostinstallRunnerAction with code ErrorCode::kPostInstallMountError
[0413/202140.977197] [INFO:update_attempter_android.cc(602)] Processing Done.
[0413/202140.989171] [INFO:snapshot.cpp(2557)] Successfully unmapped snapshot system_a
[0413/202140.991174] [INFO:snapshot.cpp(2557)] Successfully unmapped snapshot product_a
[0413/202140.993142] [INFO:snapshot.cpp(2557)] Successfully unmapped snapshot system_dlkm_a
[0413/202140.995254] [INFO:snapshot.cpp(2557)] Successfully unmapped snapshot vendor_dlkm_a
[0413/202140.997363] [INFO:snapshot.cpp(2557)] Successfully unmapped snapshot system_ext_a
[0413/202140.999516] [INFO:snapshot.cpp(2557)] Successfully unmapped snapshot vendor_a
[0413/202141.010393] [INFO:metrics_reporter_android.cc(159)] Current update attempt downloads 1903 bytes data
[0415/213538.903060] [INFO:main.cc(71)] A/B Update Engine terminating with exit code 0
[0415/213539.959401] Waited one second for gsiservice (is service started? Number of threads started in the threadpool: 1. Are binder threads started and available?)
[0415/213540.963892] Waited one second for gsiservice (is service started? Number of threads started in the threadpool: 1. Are binder threads started and available?)
[0415/213541.970464] Waited one second for gsiservice (is service started? Number of threads started in the threadpool: 1. Are binder threads started and available?)

Updating from recovery and then flashing addons again was successful.