PLA absorbs moisture, so you need to store it somehow where it cannot absorb, or at least to minimize the amount absorbed.
When I purchased my printer, it came with a spool of PLA already opened, and the exact same issue was occurring. Once I purchased a quality filament, I have never experienced this issue since. I also store any spools not being used in sealed bags with those absorbent silica packets. So far so good.
If its a new roll, then it must be a quality control thing. I cannot state enough how important it is to purchase quality material, and pay a few extra bucks. The headaches it will save you is easily worth it.
I’m fairly new to 3D printing, but this is my take on it