Just received the E62iUGS-2axD5axT today, the thing only support max 2048 on sfp1 and ether1 (the port connected to the CPU), the switchports are max 2026.
what gives? 
the max MTU isn’t mentioned anywhere, is this the SoC limitation or what? lemme ring up airoha real quick!
It has the same switch chip EN7523 as the hEX refresh and hEX S (2025). The L2MTU limit of the hEX refresh is documented here (E50UG):
The switch chip is probably very similar to the one (MT7621A) of the old hEX and hEX S too (they have exactly the same HW offload features and L2MTU limit).
So the two recent generations of hEX devices never support larger MTU.