As I was trying to replicate the issue, I added AIE.L as a security, and initially it looked like this:
Then after updating prices for the first time, prices were more consistent:
Then, after waiting a little while to let the cache expire, another price update:
After a few more updates, I managed to get the “Latest price” in the pop-up to not match the prices in any of the other locations. So yes, I agree that something doesn’t seem to add up.
I reported a similar bug only last month (here) and I thought it had been fixed, but this issue seems related. My PP version is 0.77.3, are you using the same version?