I've had many problems since going from Haxchii to Tiramisu. I don't have the answers to your questions, but I will share a few things I've observed, in case it helps.
1. I had some apps that would never launch properly, until I deleted them out manually. A clean install fixed the problems I was having with most apps. For instance, my HBL2HBC that previously worked with Haxchii no longer worked. I re-did it from scratch, and now it works. I don't se what I did different, but that fixed it.
2. When installing apps, I have had them go corrupt in transit numerous times. Try re-copying files to yoru SD, and run integrity checks on your card. I find that data sometimes goes corrupt for no obvious reason.
3. Certain Home-brew apps will crash myself system, if I launch them first after a boot. The weird thing is, if I launch another Homebrew app instead, and then launch the previously crashing apps, they will run fine. For instance, if I run the Home-brew App Store after boot, instant system lockup. If I run WUP GX2, no problem, and then run the Home-brew App Store afterwards, no problem.
Don;t get me wrong, I think Tiramisu is great. But I also think that there are some underlying issues with it, or with some apps when using it.
If you end up figuring out what was / is happening, please do write back what you found, to help out anyone who might be suffering the same problem.