Amazon Fire TV problem

Hello .

I have a problem with the Amazon Fire TV Stick for some time.
My setup looks like this:
ISP bridged to hEX (7.18.2) and hAP ax2 connected to hEX (7.18.2 all interfaces bridged as LAN, ).
The problem is that the device detects as if it has truncated internet speed
All other devices on the network seems to work fine.
The strangest thing is that when I configure the AX as a router with NAT again, the Amazon fire TV stick works normally
As a test I did the same with an old TP link router and there is the same story - when I configure as a normal switch with AP, the stick works as if it has no internet. When I make it as a router, Fire TV works normally, with full available speed
I tried disabling RSTP, no effect
Also tried to downgrade hEX to 7.15.3 with backup restore - no effects.

Have no idea why it acts like this