Frequent MS Access data corruption since 5.27.157 update

MyCloud EX2 here. Running a shop management system with three front-ends accessing a shared DB on a Windows-mapped share on MyCloud.
On October 20, the system started experiencing frequent data corruption on the shared tables, leading to significant problems in the shop’s accounting. The upgrade to 5.27.157 had taken place during the night before.

The system had been operational for nearly three years, without any issue with the shared data.
Tried rolling back to 5.26.300, will keep you posted about the results.

There have been a number of reports about file access problems when using AutoCAD programs, Paperport, etc. All after updating the OS5 firmware to version 5.27.157.

Several clues suggest that changes to the Samba (SMB) Linux package may be resonsible. but no definitive cause or solution has been found to date.