Hi,
Thank you very much for the details, it helped a lot.
I have managed to find the issue. Somehow the inline style for the search was not correctly printed, when using in an Elementor pop-up or similar column. We are already working on a better solution, which I applied to the plugins on both sites.
If you have this issue on others, please copy the whole wp-content/plugins/ajax-search-pro directory from cochraneontario.com to apply the same patch. After clearing the cache, the changes should be apparent.