Take a look at https://github.com/code-423n4/2024-08-wildcat/blob/fe746cc0fbedc4447a981a50e6ba4c95f98b9fe1/src/market/WildcatMarketBase.sol#L295-L300
This function is used to get the total balance in underlying asset and it does this by querying the balanceOf() method, issue however is that not all ERC20 support the balanceOf(), for eg Aura stash tokens, which stalls adoption and make protocol unusable with these tokens.   
QA 
Query balanceOf() on a low level.
