This has to do with stories Pinterest stories. First of all I love them. Every time I post one impressions, closeups, and saves increase overnight. This happens more than with regular pins. On the flip side, stories are hurting my stats. I use Tailwind. It increases my stats. Lately my stats have decreased. I don't understand why. Do I have to click more stories in the feed? Like them? Add more of my own stories? That is a part that's bothering me. Please help me fix this! Click on the YouTube video below. It will explain this better.
There are many variables for impressions that go beyond story pins. Although story pins may be contributing to you decline, the may only be part of the problem and only part of the solution.
If you read the posts in this community, a large number of accounts have indicated they have seen a reduction in impressions and clicks. There was a recent algorithm change which meant the "normal" activities were receiving less results.
In addition, there has been issues with statistical reporting where activities were continuing as normal, but they weren't being recorded properly. If you are using Tailwind, the app mentions that the Pinterest stats may not be accurate.
One thing you do mention is that Tailwind increases your stats. Since your focus is on story pins and Tailwind does not accept them, perhaps you have shifted your efforts away from your source of traffic. In working on story pins have you continued with the same volume of regular pins and tribes? Some say that 30%-50% of their traffic comes from Pinterest tribes.
So there are some adjustments being made by Pinterest. Story pins can not get click throughs so that may affect your metrics. Last of all, you may have shifted your focus from regular pins that were working to story pins which have different types of traffic patterns.
Keep trying different things and monitoring your stats until you find something that works.