I had this problem. I deleted the button and reinstalled it and the problem was gone.
However (don't we hate that word), my project is a 2 door garage door opener. Yesterday
I noticed that one of my OPEN LEDs was not working. I reset my Wemos D1 and nothing
worked. I checked and the entire sketch was gone. I reloaded it and it worked then I unplugged
the USB from the laptop and plugged it back into the power supply and nothing. Sketch was gone
tried another board and got the same results. Finally determined that it was the OPEN LED pins.
I think that I need to add Pullup resistors. I removed them from the circuit and the sketch stayed and worked. However (here we go again), now the Right door comes up on power up. I deleted the button and reinstalled it. Right door didn't come up on power up...however (), the left one did. Deleted and reinstalled it, left works and theright comes up on power up. Deleted both and reinstalled both and the left comes up on power up. I walked away before I inflicted severe damage to the circuit!
I think the problem is with Blynk some how. Before I installed a DHT22 in the equation the Delete/Reinstall worked and the problem did not jump to the other button.