Cheers, steph_giles.

Yes. There seems to be bug with 1Password's locking is set to "never" is set on some systems. The progress we've made so far, after ~6 months of this syncing bug. I'm hopeful 1Password has enough information now to get to the bottom of this bug, instead of me testing more & more.

Lock 1Password as soon as possible

Lock 1P ASAP Test Results: one B5 error in 116 hours (0.20 sync errors / day)
Start of "lock 1P ASAP": March 16, 2023 at 12:30pm
End of "lock 1P ASAP": March 21, 2023 at 9:20am
Duration: 116 hours, 50 minutes
B5 errors: 1 (one!)

Never lock 1Password

Never Lock 1P Test Results: 128 B5 errors in 171 hours (18 sync errors / day)
Start of "never lock 1P": March 21, 2023 at 9:30am
End of "never lock 1P": March 28, 2023 at 1:10pm
Duration: 171 hours, 40 minutes
B5 errors: 128 times