Im not 100% sure if this broke in this update or in the last, but now the individual tracker options seem to work a little differently. "peerid:TIX0243-" goes to the tracker as "IX0243-", the first letter disappears somewhere. "peerid: TIX0243-" works (doesn't need to be a space, any letter works). Not sure about other options like header. (You can see this easily by spoofing any tracker and looking at torrent options>peers>local peer id)

Now they have my incorrect peer ids all over their logs >:-E

But I also want to thank you devs for your work, youve added features ive requested and fixed bugs ive reported. Best client out there too.

It's broken since v2.49. Tixati v2.48 works fine with the same settings. Not only peer id but also other Individual Tracker Options on Advanced Options tab are affected.

SOMEthing about parsing the first character off.
If you change your peerid to "TTIX0243, or rather TTIX0249-laskjdflakj" it sends out for TIX(ati version)2.49

get v2.51. this is fixed.