Resolved JCE Stripping Script Src URL

I'm trying to add a code for a Rafflecopter competition widget into an article. The code contains script src="url", which is stripped out every time I toggle from code view to Editor view.

I have used the Rafflecopter code before with no issues, although not for a while so they may have changed something.

I have JCE set to allow Java, and Joomla Global Config set not to strip code, but this issue persists. I tried adding a custom config variable to JCE, allow_script_urls=true, but this doesn't seem to have helped. Any ideas?

JCE pro 2.8.15 and Joomla 3.9.20