I think the only time you should have seen that prompt was when the switch was made from Yahoo to Google.

If your change gets overridden, could you check for a user.js file in your profile? The following article has a section on tracking that down: How to fix preferences that won't save.

Yes there is a partnership with Google as Mozilla is a non-profit organization, as there was a previous one with Yahoo until sold to Oath/AOL and before that it was Google again.

But Mozilla would never stoop so low as force changes or badger someone. as the software comes installed with other choices and ability to make own decision as you have. There possible is a setting wrong, or a corrupted file and the next thing you would have been asked is Firefox is not performing well we can help make it faster for a Refresh.

Some times you get lucky with the millions and millions of different browser configurations, software and add-ons and .....

So glad you found the setting to do that. Good Job.

Could you mark your Question as solved with the question as the solution please if possible. hanks.

Ok well its happened more than once after updating to Quantum so I suspect there is a bit of stooping going on. If Google is their default and I've completely removed it from my search engine list, it tries to get me to switch until I change the configuration flag to stop asking. Not a big deal as I understand they need to make a profit to pay their employees, just never experienced this kind of thing in Firefox since this year. Will update as solved. Thanks.