I noticed the exact same change. I work in IT and have for 30 years. Clearing a browser's cache is not the solution.
I am on a 206-day streak at the moment, and I have been missing out on 200 points per day because of the Bing searches not rewarding beyond 20 points. I typically could collect all of the rewards possible per day within 3 minutes.
Today, I ran across an article that states Microsoft has changed the rewards system when it comes to Bing Searches. Three searches can earn points per every 15 minutes.
Here is the link to the article. It's disappointing that it has come to this.
https://www.windowscentral.com/software-apps/browsing/the-microsoft-rewards-program-is-seemingly-back-to-normal-with-users-getting-up-to-30-points-per-reward-again
Have a great one,
Digital99x
The program seems to have reverted back to its former self (knocking on wood).
I agree with another commenter on this forum that it looks like Microsoft was crippling the Rewards program during the holiday season, and now that it's over, things are going back to how they were. I'm still not 100% confident in this change, however.