I reported this bug back in 2023, and it still exists today.
When I log into my firefox account on a new PC, those icons on the Firefox home page are history instead of URLs I've already pinned and synced on another device, and this cluttered history overwrites the URLs I've already pinned, causing the Firefox home page on my old device to be overwritten by history as well, and all of those icons I pinned are lost! I've had this problem many times over the past two years, and unfortunately mozilla has never fixed it.
My own solution was to install a special Firefox to record the pinned homepage and then freeze it, and when the homepage was corrupted I open the frozen Firefox and quickly drag the pinned icon position a few times, so that the homepage could overwrite the cluttered history again.
But this is not a perfect solution after all, I hope to see the bug fixed one day.
