I faced the following problem when working with MySQL 8 and HMM 13.3.15068.0: When changing the tags via tag editor HMM still shows the old values after stroing the data. The tags are saved correctly in the flac-file. When renaming/moving the files the old values will be used.
Example from my HMM installation
We have made some firsts tests related to this and it seems to be related to MySql verison 8 only.
The test fails with a small MySql8 database, whilst it works with a large MariaDb as well as a Sql Compact database.
As it seems it is the MySql driver that throws a low-level error from it's process.
We will continue to analyse this.
Thanks for reporting.
We have hopefully found a solution for this which we will need to test a bit more before we can release a new version.
If you would like to participate in the testing, please contact us over http://support.imploded.com
This should be resolved in the hotfix for Helium 13.3 which is just released.