Weird Glitches making real time stuff painfull

Hey there,
I’m using the following:

Steinberg UR22 Interface w/ Yamaha Steinberg USB Asio Driver v1.9.9

FL Studio 12.3 (Default Samplerate etc.)

Windows 7 with 16GB DDR4 Ram and a intel i7 6700k CPU

And my problem is as follows:

I’m getting some weird glitches whenever i press play in my DAW. The Time Marker of the playlist seems to instantly start moving without audio playing, then jumps back, cracks a few buffer sizes long (like a normal underrun would sound), then starts playing regularly. When i have analog hardware connected and want to feed midi into it and spit audio back into FL studio for example, a nasty, high screech sound appears on the channel where i feed my audio in (so when i have for example delay effect on that channel, it is also applied to the screech sound). it’s very painfull and makes it not so fun to work with. all those problems appear at buffer sizes up to 1024 samples +, however my CPU is pretty badass and once a project is playing, it can handle pretty much everything with buffersizes of 128 or even 64 samples. i have checked my system latency with the tool “DSP latency checker” and i’m allways in the green area (mostly under 50 microseconds and sometimes peaks around 400 microseconds).
I dont remember that problem from my old system that probably had another version of the usb driver.

is that a known problem? what am i supposed to do?

thanks a lot in advance!