I would like to contribute as much money to my 403(b) as possible this year, and I certainly want to take advantage of any employer matching. It is my understanding that employer contributions do not count toward the IRS's individual contribution limit for retirement accounts. I know that this is the case with the TSP as well as 401(k) accounts as described here, here, and in many other places besides.
In my current position, however, I have a 403(b), and my employer is telling me that I should not contribute the full $19,500 for 2020 because I would then not be able to receive the full matching amount. They are referring specifically to the individual IRS contribution limit, not the combined employer/employee limit. I have not been able to find any evidence that 403(b) plans are different from 401(k) plans in this respect; on the contrary, both the IRS website and this article seem to agree with me. Is there something I am missing? If I am correct, how should I handle the conversation with my employer politely? It seems impertinent to correct someone in their official capacity.