Upgrade task 552 can fail on it first run and then pass on it second run without converting lots of the data.

Scenario:

1. Upgrade fails during - updateSearchRequests();
2. On second run no customFieldGVs are returned as they were updated in bulk prior to the error above.

This will leave the system in the following state:

1. Some search requests will not have been upgraded
2. updateGadgetConfigurations wont have run
3. customFieldManager.removeCustomFieldPossiblyLeavingOrphanedData wont have been run
4. ofBizDelegator.removeByOr(CF_VALUE_ENTITY, "customfield", customFieldIds); wont have been run

All possible issues (that I can think of):

1. Field Screens & Field configs with Label custom fields may have issues
2. Filter defined columns, user defined columns & system defined columns with Label CFs may have issues
3. Any thing that relies on a search that includes a Labels CF may have issues
4. Gadgets that used Label CFs may have issues

They should restore, fix the issue and re-upgrade.
If this is not possible, they should contact support.