You might be remembering how the Catch Up amount works, if there are two plans:

"If Joe Saver, who’s over 50, has only one employer in 2020 and participates in that employer’s 401(k) plan, the plan would have to permit catch-up contributions before he could defer the maximum of $26,000 for 2020 (the $19,500 regular limit for 2020 plus the $6,500 catch-up limit for 2020). If the plan didn’t permit catch-up contributions, the most Joe could defer would be $19,500. However, if Joe participates in two 401(k) plans, each maintained by an unrelated employer, he can defer a total of $26,000 even if neither plan has catch-up provisions. Of course, Joe couldn’t defer more than $19,500 under either plan and he would be responsible for monitoring his own contributions.

The rules relating to catch-up contributions are complex and your limits may differ according to provisions in your specific plan. You should contact your plan administrator to find out whether your plan allows catch-up contributions and how the catch-up rules apply to you."

From: https://www.irs.gov/retirement-plans/plan-participant-employee/retirement-topics-401k-and-profit-sha...