Dear @controlplusf i have check plugin on my localhost, the thumbnail resize functions still working, i think your problem because wrong in short code setting, please kindly give for me admin account via private reply, i will check detail to help you.
Dear, i think this problem because your site load script is slowly, in first page load, SCRIPT not save in cache, after page load the script saved in browser cache, to fix it, you can speed up page load , you can read more in HERE
