B/G can connet with rate from B to G-only MT AP

RouterOS General
1

Hi!
Why APC (like tp-link 543g) in B/G mode (is no posibility to change it to g-only) can connect to G-only MT AP with rx side rates from B?
For example we can see on Wireless Registration table:
18/1, 18/5.5, 18/1

UBNT Fixed this bug in their firmware.

But in MT - no change.