Change:
Server CID will collide with Source CID.
This is often used to mean Source Connection ID in other contexts. A collision here is likely to cause confusion.
Recommended name? SCCID?
I think it might just be best to call it the "Server CID" any other abbreviated term will get confused IMO.
"Server CID" doesn't seem to fit well with "Stream Cipher Connection ID"
So SCID didn't mean "Server Connection ID"? There is definitely confusion here. I'd just recommend not abbreviating anything more than CID.
I guess this proves MT's point. "STream Cipher Connection ID" (just like PCID, OCID, BCID)
Looking again, the document never uses any acronym for 'stream cipher connection ID', so there's no issue there. This is just about 'S' meaning "source" or "server".

Discussion:
server using QUIC or another protocol, are treated as a server with respect to this specification. <ins> For brevity, "Connection ID" will often be abbreviated as "CID". </ins> 2. 2.1.

4.1.1. The configuration agent selects a number of bytes of the server <del> connection ID (SCID) to encode individual server IDs, called the "routing bytes".  The number of bytes MUST have enough entropy to have a different code point for each server. </del> <ins> connection ID to encode individual server IDs, called the "routing bytes".  The number of bytes MUST have enough entropy to have a different code point for each server. </ins> It also assigns a server ID to each server.

4.2.1. The configuration agent selects an arbitrary set of bits of the <del> server connection ID (SCID) that it will use to route to a given server, called the "routing bits".  The number of bits MUST have enough entropy to have a different code point for each server, and SHOULD have enough entropy so that there are many codepoints for each </del> <ins> server connection ID that it will use to route to a given server, called the "routing bits".  The number of bits MUST have enough entropy to have a different code point for each server, and SHOULD have enough entropy so that there are many codepoints for each </ins> server. The configuration agent MUST NOT select a routing mask with more than

4.2.2. Upon receipt of a QUIC packet, the load balancer extracts the <del> selected bits of the SCID and expresses them as an unsigned integer of that length.  The load balancer then divides the result by the chosen divisor.  The modulus of this operation maps to the modulus for the destination server. </del> <ins> selected bits of the Server CID and expresses them as an unsigned integer of that length.  The load balancer then divides the result by the chosen divisor.  The modulus of this operation maps to the modulus for the destination server. </ins> <del> Note that any SCID that contains a server's modulus, plus an </del> <ins> Note that any Server CID that contains a server's modulus, plus an </ins> arbitrary integer multiple of the divisor, in the routing bits is routable to that server regardless of the contents of the non-routing bits.  Outside observers that do not know the divisor or the routing <del> bits will therefore have difficulty identifying that two SCIDs route to the same server. </del> <ins> bits will therefore have difficulty identifying that two Server CIDs route to the same server. </ins> Note also that not all Connection IDs are necessarily routable, as the computed modulus may not match one assigned to any server.  These