When a hold request is placed, Polaris performs an eligibility evaluation only once—at the moment when the request is first placed. Polaris does not re-evaluate eligibility later. So if Polaris is configured to use hold trapping preferences that prefers "my patron" but some temporary circumstance prevents the assigned library's item from filling a hold for the library's patron, the hold must now be filled by a different library. This can be mitigated if staff notice the problem and delete and replace the hold, but this is a lot of extra overhead and in all likelihood the problem will go unnoticed. The result is that the trapping preference is not honored, and the patron may need to wait weeks for their hold to be filled even though their library owns a copy.