Infotainment randomly rearranging my albums

Hi all, I've painstakingly uploaded all my CDs to a usb stick and finally managed to do it right to play on the Yeti's Bolero system. All working beautifully. All albums in alphabetical order with artwork, just a flick of ya finger and scrolling through albums, perfect. But in the last few days for some unknown reason the albums are jumbled up & a large amount of albums have been put into one file right at the beginning named 'Untitled'! Not in their groups, just a huge list of random songs!

If it was all working perfectly, how has it changed??

This is driving me crazy! Please help. Thanks

Apart from this, it's a pretty perfect family car