Output of the 555 pin 3 high when power on
I think a possible solution to this issue can be using some pull-up resistor on the trigger pin. By default, the trigger pin is high and makes the output goes low. A large value resistor can be used. If the pin is kept floating, it can take any value between 0-5v as input so may behave unexpectedly.

Using a resistor ensures the input is tied to the ground or Vcc and not left floating around, which may be causing the issue.
I think this solves the problem.