Submitted by IllIllI, also found by Lambda and cccz
https://github.com/code-423n4/2022-12-tessera/blob/f37a11407da2af844bbfe868e1422e3665a5f8e4/src/modules/GroupBuy.sol#L114-L150 
https://github.com/code-423n4/2022-12-tessera/blob/f37a11407da2af844bbfe868e1422e3665a5f8e4/src/modules/GroupBuy.sol#L301-L303
If a user contributes funds after there is no more supply left, and they dont provide a price higher than the current minimum bid, they will be unable to withdraw their funds while the NFT remains unbought.
Ether becomes stuck until and unless the NFT is bought, which may never happen.
When making a contribution, the user calls the payable contribute() function. If the supply has already been filled (fillAtAnyPriceQuantity is zero), the bid isnt inserted into the queue, so the new bid is not tracked anywhere. When the function reaches processBidsInQueue():
https://github.com/code-423n4/2022-12-tessera/blob/f37a11407da2af844bbfe868e1422e3665a5f8e4/src/modules/GroupBuy.sol#L99-L150
if the price isnt higher than the lowest bid, the while loop is broken out of, with pendingBalances having never been updated, and the function does not revert:
https://github.com/code-423n4/2022-12-tessera/blob/f37a11407da2af844bbfe868e1422e3665a5f8e4/src/modules/GroupBuy.sol#L291-L313
In order for a user to get funds back, the amount must have been stored in pendingBalances, and since this is never done, all funds contributed during the contribute() call become property of the GroupBuy contract, with the user being unable to withdraw...:
https://github.com/code-423n4/2022-12-tessera/blob/f37a11407da2af844bbfe868e1422e3665a5f8e4/src/modules/GroupBuy.sol#L274-L284
until the order has gone through, and they can claim() excess funds, but there likely wont be any, due to the separate MEV bug I raised:
https://github.com/code-423n4/2022-12-tessera/blob/f37a11407da2af844bbfe868e1422e3665a5f8e4/src/modules/GroupBuy.sol#L228-L244
revert() if the price is lower than the min bid, and the queue is already full
stevennevins (Tessera) confirmed and mitigated:
