Q:

macOS Catalina: execute bash script on boot with launchctl

Before updating to Catalina (10.15.1) my agent based on a bash script was working perfectly. 
I had set the agent in order to execute the bash script on boot.  
Here is the plist file:
<? xml version="1.0" encoding="UTF-8"? >
<! DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
    <dict>
        <key>Label</key>
        <string>mark.battery.info</string>
        <key>Program</key>
        <string>/Users/mark/Dropbox/Exec/BatteryInfoOnBoot.sh</string>
        <key>RunAtLoad</key>
        <true/>
    </dict>
</plist>

After the last update I noticed that the script (BatteryInfoOnBoot.sh) was no longer loaded at boot and if I execute the command:
launchctl list | grep mark
-   1   mark.battery.info

I read that the status 1 means:

PID - Status 1 means that the process doesn't have enough privileges
  to access some files

ref
The script BatteryInfoOnBoot is very simple:
#! /bin/bash

echo "~~~~~~~~~"  >> /Users/mark/Documents/battery-log.txt
date  >> /Users/mark/Documents/battery-log.txt
/Users/mark/Dropbox/Exec/BatteryInfo.sh >> /Users/mark/Documents/battery-log.txt

instead BatteryInfo.sh is used only to get some useful info:
#! /bin/bash

echo "Current battery percentage:"
pmset -g batt | grep -Eo "\d+%" | cut -d% -f1
echo ""

echo "Cycle count:"
system_profiler SPPowerDataType | grep "Cycle Count"
echo ""

echo "Capacity stats:"
ioreg -brc AppleSmartBattery | grep -i capacity | grep -v Legacy | grep -v BatteryData | grep -v AppleRaw
echo ""

PS: the script is still working if I exec it manually:
/Users/mark/Dropbox/Exec/BatteryInfoOnBoot.sh

Any suggestions? 

A:

/Users/mark/Documents/ is a protected user folder (as Downloads and Desktop). 
Usually you can add applications to System Preferences > Security & Privacy > Privacy > Full Disk Access to enable access to these folders.  Terminal is already added probably - the reason why no error is shown executing the script manually. 
Change the destination of the log file in the shell script BatteryInfoOnBoot.sh to /Users/mark/Library/Logs/ and it will work. 
Proof (Virtual machine - no battery inside ;-)):
user@host ~ % cat Library/Logs/battery-log.txt 
~~~~~~~~~
Tue Dec  3 01:23:55 CET 2019
Current battery percentage:

Cycle count:

Capacity stats:

As an unwanted alternative (because even a-typical log files belong to ~/Library/Logs/ or /Library/Logs/) you can keep your original file as it is but you have to add /bin/launchctl to System Preferences > Security & Privacy > Privacy > Full Disk Access then. 
Proof (still no battery inside):
user@host ~ % cat Documents/battery-log.txt 
~~~~~~~~~
Tue Dec  3 01:32:30 CET 2019
Current battery percentage:

Cycle count:

Capacity stats:

