database and tables became invisible

We have the problem that our databases and tables became all of the sudden invisible during runtime. SHOW DATABASES and SHOW TABLES stopped returning anything. Nevertheless SELECTs and INSERTs still work if the correct database/table name is given. The error logs do not contain any information. Restarting the database does not resolve the problem. There were some changes to the database layout around the time when the problem set in, three additional tables were added and one unused table was deleted but it is uncertain if this caused the problem.
The problem is independent of the user and it's permissions. The root user can not see the databases, neither can a newly added user that has every permission possible. The skip-show-database option is definitely disabled.

Is there a general problem with running MariaDB on 32bit windows systems? We have experienced a bug that resulted in data loss before which was fixed in 10.1.14, so we are a bit concerned.