Submitted by rvierdiiev, also found by __141345__ and UniversalCrypto
https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/Trading.sol#L235 
https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/Trading.sol#L847-L849
Approved operators of owner of Position token cant call several function in Trading.
Functions that accept Position token in Trading are checking that the caller is owner of token using \_checkOwner function. 
https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/Trading.sol#L847-L849
As you can see this function doesnt allow approved operators of tokens owner to pass the check. As a resul, functions are not possible to call for them on behalf of owner.
For example here, there is a check that doesnt allow to call initiateCloseOrder function.
VS Code
Allow operators of tokens owner to call functions on behalf of owner.
Alex the Entreprenerd (judge) commented:
GainsGoblin (Tigris Trade) acknowledged and commented:
