Thank you for contacting Rank Math and sorry for any inconvenience that might have been caused due to that.
The issue is arising from your caching plugins since the functionality is restored as soon as the page cache is cleared. I can suggest that you get in touch with the authors of this plugin so that they can advise on how to fix this.
I can suggest that you clone your site to a temporary staging domain and then deactivate all other installed plugins and check whether this problem will still be reproduced. I can suggest that you use the following plugin to help in setting this up https://wordpress.org/plugins/duplicator/