Submitted by cryptphi, also found by adriro, Ch_301, PaludoX0, ayeslick, and perseverancesuccess
https://github.com/debtdao/Line-of-Credit/blob/audit/code4rena-2022-11-03/contracts/modules/credit/LineOfCredit.sol#L143
https://github.com/debtdao/Line-of-Credit/blob/audit/code4rena-2022-11-03/contracts/modules/credit/LineOfCredit.sol#L83-L86
The modifier whileBorrowing() is used along in the call to LineOfCredit.declareInsolvent(). However this check reverts when count == 0 or credits[ids[0]].principal == 0 . Within the contract, any lender can add credit which adds an entry in credits array, credits[ids].
Assume, when borrower chooses lender positions including credits[ids[0]] to draw on, and repays back the loan fully for credits[ids[1]], then the call to declareInsolvent() by the arbiter would revert since it does not pass the whileBorrowing() modifier check due to the ids array index shift in the call to  stepQ(), which would shift ids[1] to ids[0], thereby making the condition for credits[ids[0]].principal == 0 be true causing the revert.
The modifier whileBorrowing() would need to be reviewed and amended.
dmvt (judge) increased severity to High
kibagateaux (Debt DAO) confirmed
