Kate Horrell and Military.com did a great job of interrogating DFAS, who has continued to be annoyingly quiet about this problem. Kate and I learned of it from readers e-mailing us about the issue.
What started as a software change (to make it easier for age-50+ catch-up contributions to the TSP) has royally screwed up the cash flow of servicemembers who front-load their TSP accounts. (Front-loading is fine if you're in the legacy High Three pension system, while you should not front-load if you're in the Blended Retirement System with matching DoD contributions to your TSP.) This glitch might not be noticed by federal civil-service employees either (who get matching TSP contributions as well) unless those employees are also Reserve/Guard members with a uniformed services account.
Now lots of readers have been chiming in about their excess contributions. This is a DoD-wide issue for pay handled by DFAS.* It's also an issue affecting people who are trying to contribute Combat Zone Tax-Exempt pay to their TSP above the elective deferral limit ($19.5K in 2021).
So yeah-- if you front-load your TSP then you need to check your LES for your contributions to date, and consider dialing back the percentage to avoid going over the EDL. Otherwise DFAS will take a couple months to refund your excess.
I've added more gory details in this post:
https://the-military-guide.com/did-dfas-and-the-tsp-let-you-contribute-too-much/(* Coast Guard servicemembers seem to be fine as long as their pay is coming through DHS and not DoD/DFAS.)
