text being deleted upon update of changes to pages/posts

I haven’t noticed this issue before the 3.6 update, but it is extremely frustrating to write a few hundred words of text only to have it mysteriously vanish into nothingness upon ‘update’.

I have identified that it has something to do with lettering from alphabets other than the standard a-z English alphabet. Insertion of letters with dots and lines above and such.

Is there some sort of remedy for this?

Thank you in advance for your assistance.