We are resolving this incident as we have not observed any user impact from the Slack multi-select dropdown issue since approximately 7:15pm UTC yesterday. While Slack have not officially confirmed a fix on their end, all functionality appears to be restored and no further reports have been received.
We'll continue to monitor for any recurrence and will re-open the incident if necessary. Thank you for your patience while we worked through this issue. If you experience any further problems, please let us know.