Any reason why {% requirePermission 'editEntries:1' %} would stop working within the past week or so?
Assuming you've recently updated to Craft 3.1, if you look in your userpermissions table you'll see that they're now lowercase and using UIDs rather than integer IDs, like this:

editentries:3bb69b06-3e65-4ae5-8d70-6c47c1a88fbe


The only place I can find anything like this documented is in the "Updating Plugins for Craft 3.1" guide

https://craftcms.com/guides/updating-plugins-for-craft-3-1#update-element-source-key-references