iTunes Match Deleting content

I have been using iTunes match for several years now. It has been a very convenient service. With over 200GB of music, being able to access it on all my devices wherever I go for only $25/yr has been totally worth it. However recently I have noticed an issue where songs are being deleted from my library without prior knowledge. I can't say for sure when this issue began, but as I scan my library now I would estimate that 1 in every 5 of my albums is missing tracks!! This is very unfortunate considering I trusted Apple with my music under the assumption that it would be preserved and also matched with even higher quality bitrates when played back. Has anyone else experienced this?