Antique Poison Bottle Won't Stand Upright

Hello! This amber-colored bottle has the word POISON on the side. It basically has 3 sides (two sides are flat and one is rounded). Three edges are hobbed (I think that is what it is called). On the bottom is 67 and another mark which looks like it could be F. The bottle is 3 1/2 inches in height and 1 7/8 inches wide. My question is: The bottle does not stand upright, because the base is not flat! I am wondering if this is a purposeful thing, or whether the bottle somehow became misshapen? Would appreciate any information about this antique bottle. Thank you!

 

Some information here ...
https://www.collectorsweekly.com/bottles/poison-bottles

 

Going by the shape, I would suggest that it was one of three bottles which were intended to be stood up in some sort of circular frame.

 

Could be the bottom was mishapen. Poison bottles were made with the 3 sides knobbed so you can tell they contain poison just by the touch if you picked the bottle up accidentally at night or without your glasses on. I have no idea about the marks on the bottom.

 

Could it have been near a bonfire? Not enough to destroy it but just to misshape it?