Hello tommsch, This is not an expected behavior and certainly not a bug. This can be checked by searching the file 'mdbstatus.m', The file can be found in …\toolbox\matlab\codetools in your installation directory, i.e : C:\Program Files\MATLAB\R2016b\toolbox\matlab\codetools. Search the file in this folder.
To add, resolving your issue needs further information. Reproduction steps are also important to investigate the issue. Please add information regarding the same.