Just for your information:

All the public free relays that I am aware of, only store your kind-4 up to a limit. I don't know the exact time or storage limit, but 7-days is a good estimate.

Blowater store your kind-4 locally so that you always feel like no history is missing. However, if you clear browser data or login with another browser, you can only see recent data.

This is not a bug. Public free relay operators are using their own money to serve all of us, it's not reasonable to ask them to store our notes forever for free.

I am not sure how posts are stored in these relays because Blowater is not a social client.