I looked into message / qksms with the misattribution issue in the past: Messages issues: not syncing, not backing up, and texts going to wrong threads - #2 by tcecyk and found upstream bug tickets and recommended update.
The upcoming /e/ 1.0 release is updated to current qksms 3.9.4 (Import OKSMS v3.9.4 update in Message app (#5037) · Issues · e / Backlog · GitLab). Wonder if you still experience your issue after the update