Initial search for "block by slot" can hang with indefinite loading spinner

[catch-21]

Summary

The first time querying for a Block by Slot can find the block but doesn't show page content, loading spinner is displayed indefinitely. Although, once the block page has been loaded (e.g. by direct navigation) then the query works as expected.

Steps to reproduce

1. Navigate to https://explorer.alonzo-purple.dev.cardano.org
2. Type 360 into search field
3. Click on "Search for a block by slot"

Actual Result

No results shown. Loading spinner shown indefinitely.
Url does display correct block query - at this stage if you diretly navigate to this url (click in url bar and press enter, or hit refresh) then follow steps again then it desired result is produced. Refreshing at homepage will cause the issue again.

Desired result

Block for slot 360 details are displayed.

Screenshot of actual result