BUG: Caching "fails" if using search without trailing slash

If I go to this url:
https://www.r-statistics.com/search/heatmap
It will recreate the cache everytime I refresh the page (see the source at the bottom, you can see the cache date refreshes everytime).
However, if I go to (notice the slash at the end):
https://www.r-statistics.com/search/heatmap/
The cache is solid and does not refresh.

I manually fixed it by using the following htaccess: http://stackoverflow.com/questions/7780859/htaccess-rewrite-to-force-trailing-slash-at-the-end
But I suspect this is an undesired behavior that you would wish to fix.

Thanks.

Reproduce the issue using the two search URLs in the report and compare the cache date shown in the page source after refreshing each one. Trace the cache handling for slashless and trailing-slash requests, using the reported htaccess rewrite as context. Done means repeated refreshes of the slashless URL reuse the cache without requiring a manual rewrite.

Written by the indexing model from the issue text.