Wow, I haven't booked anything on AC/Aeroplan for ages. Things have changed!!

I had issues with booking a reward trip this past weekend. The AC site wasn't cooperating and I had to re enter my dates repeatedly. I finally got some flight reward choices to load and discovered that my YYC-YUL (return) flight selection had Premium Economy seats for less points than Economy Flex or Latitude seats. I chose the flights, PE seats, noting the points required were 17,700 and 20,000 respectively per direction. Plus total fees of $91 ish.

On the final page, the fees were correct but the points had somehow increased to 48000. And my name had posted incorrectly, combining my first and middle names as one. In trying to correct the name and points errors, the site got hung up. Repeatedly.

In the end, a frustrating hour later, I just booked at the higher, incorrect points level (48000 instead of 37700) I have subsequently discovered that booking the same itinerary as two one way award flights, the points required (17,700 & 20,000) and the total taxes are correct as indicated on the selection page and on the final booking page.

Does anyone know what was going on with the random increase in points required? Why did this occur on a round-trip reward only? I did book on Saturday, so almost 40 hours ago, but is there any recourse in being charged 48000 points instead of 37700 as I had chosen? Is it a known website Aeroplan booking glitch?

Any insights appreciated.