There may be two parts to this sort of problem, the state of the reel and the way it is loaded.
As everyone knows, the reels need to be dry - they also need to be clean. Soak in warm water and household bleach, rinse, scrub, rinse, soak in clean water, rinse and dry. That should take care of that. This is an annual-maintenance sort of thing, but if you have unknown secondhand reels it is a sensible precaution before use.
Watching colleagues trying to load a reel in daylight (using scrap film, and with their eyes closed) it seems that when people get a little bit stressed they often push the reels together 'to make it grip', or completely by accident. All that does is produce friction between the reel and the outside edge of the film.
If there is a tricky bit, try waggling the two parts of the reel out of parallel a fraction, even with a little shake to relax the film again. In any case always consciously avoid pushing the two parts of the reel together. Hundreds of thousands of people are using these plastic reels without a problem, just as with the steel varieties.
I doubt it's an ektar issue. I've loaded hundreds of rolls of that on patterson reels, and generally it's fine.