If you work in a related field (e.g. digital agency, web development company, devops), check to see if you signed an employment agreement or confidentiality agreement.

Read it carefully, then imagine if you did a side project relating to what your current expertise is, for Automattic on the weekends.

Then ask yourself if it would violate your agreement.

It might not, or you might not have such an agreement, but we do and I think (although IANAL) this does not sit well with that agreement.

If you do have a conflict, they're normally willing to work with you on how the trial is structured. If I had been under such a non-compete, personally, I'd probably have just done the trial unpaid as a targeted contribution to an open source project or something. Which is very rarely going to be a conflict of interest. :)

tl;dr: they're normally willing to work with you if there's a problem.

Most Anglo Saxon legal systems do and with the US at will they could sack you just like that anyway.