Binance Bridge (Proof of Collateral)

It seems that the BSC bridge is flawed. If my assumption is correct, more than $25M of tokens that were meant to be burned, were in fact sent back to Binance. I'll make the case for StepN (GMT) here.
Binance creates liquidity for 97 different projects on BSC through their bridge. In order to keep the circulating supply constant, they lock an equivalent amount of tokens in the source chain. The addresses can be checked on their 'Proof of Collateral' webpage.
The chart below displays the circulating supply of #GMT on BSC (in blue) against the number of GMT held as collateral by Binance on Solana. Since May 24th, Binance has always ensured that it held more tokens as collateral vs the circulating supply. That's good.
StepN is a mobile game in which users burn GMT to perform certain in-game actions and decrease the supply. All these daily burns are showcased by the gradually decreasing blue curve (circulating GMT supply). But on Solana, the amount of tokens remains constant.
What we'd expect
Ideally: For every burnt GMT token on BSC, burn an equivalent amount of tokens on Solana. Both graphs should reduce gradually through burns
Possibly: Instead of burning the GMT tokens on Solana, they could be permanently locked but this is less transparent.
What we observe
The GMT tokens which serve as collateral aren't burned but instead sent back to Binance and thus brought back into circulation. This would mean that the burns on the BSC realm are basically pointless when it comes to GMT supply reduction.