Corrupt musescore files

Hello,
Firstly, thanks for the remarkable software.
I noticed file corruption in a very usual mode of work. A file seems to be OK, then it reports corruption at next opening. Several measures are corrupt and while they should be 4/4, a rest is inserted where it should not be. This has happened before, too. Please look at the attached file and advise how to repair such errors.
Thanks,
Joseph Levi
joseph@transprint-bg.com, joseph_tp (Skype)