Elements 2020 freezes in playback of an MP4 file

Thanks. The Adobe contact will be useful --- hopefully. In the meantime I'm trying to zero in on the specific problem. Initially I wanted to combine into a movie a dozen MP4 videos that I had made and recorded on my Elements 14 - one for each day of an overseas vacation. Total about 50 minutes. My brand new Elements 2020 on a brand new gaming computer couldn't cope with it. Everything I tried had the track highly compressed - simply so I could see everything on the track. I always worked that way on Elements 14 with no problem. But on the 2020, the playback, rendering  or recording froze after 10 seconds of handling the comressed data. 

Then the light went on.   I tried playing, and then recording, a few short clips stretched out as far as possible along the track. I could barely see 2 minutes of data on the width of the screen. But it worked! No freezing - and three times as fast as my Elements 14. I then recorded my 50 minute movie in less than 20 minutes.

In practise, I no longer have a problem. My workaround is to never compress the data on the track. But why is my brand new kit not as functional as my elements 14 on an old computer?