Just posted about this issue as well. I'm not sure Bungie even cares based on the lack of response about this issue

Good luck receiving any help, I've submitted multiple tickets and haven't heard anything.

I've had a similar problem myself. I haven't played Destiny since late 2020, but I've been claiming the monthly Twitch Prime Gaming rewards since January 2021 (the first month I had Twitch Prime active) in case I felt like playing again which I recently have. However, upon checking my Partner Rewards page here on Bungie.net it is saying that I only have the 13th and 36th rewards (the first reward I claimed in Jan 2021 and the most recent reward for Feb 2023 respectively) available to collect from Amanda Holliday at the Tower. I've clicked the Refresh button but the 14th through to the 35th rewards (Feb 2021 to Jan 2023) aren't showing-up here on my Rewards page despite my Twitch account confirming I've claimed them and they were sent to my Bungie.net account. While I also heard about Twitch rewards expiring, it doesn't make sense to me that my first reward from Jan 2021 would still be available but my rewards from the past 6 to 12 months would all be gone. My recommendation for this issue is to take screenshots of all individually claimed Twitch Prime Gaming monthly promotions so that, if Bungie.net staff want confirmation we claimed them, they can see they were recorded as being "Delivered" on Twitch's end.