Is Brain.js affected by the moment I run my script?

I'm trying to adjust weights of my script. I noticed that the first time I'm running it, my result are often worse than the next runs.

Once I had results like:
first time:
training error: 10
second time:
training error 0.1

I didn't change anything between both times. This is the most extreme but this is not the first time I'm noticing this. This is not always the case but my worst results are always the first time I'm running the script.

So that I'm wondering: is there a little memory, something like this or is this just some coincidence? May it affects my results once the model is exported?

Thank you