Contact support to request download links for the following SPRs to receive hotfixes for “the collection has become invalid”:
For iSeries servers: PTF L502868 hotfix for SPR CSCT836HFL
For Windows Servers: Hotfix 851FP1HF154 related to Technote 1396849 and SPR# CSCT836HFL
FOR CLIENT-SIDE:
The currently available hotfixes only address the server-side lookups. Any lookups performed on the client side still potentially have this problem.
NEW SPR # MWID83NSL7 is for the client-side issues. Readers: Please dogpile into this SPR to get it weighted, as the current line from support is that no hotfix will be created, so you won’t have a fix until maybe an 8.5.1FP3 “in a couple months”.
I will cross-post elsewhere.