Thanks in advance for your advice.
I've been a successful diyer for decades but now I'm stumped. Or maybe I don't like the probable solution.
Here it is.
This is an old school faucet assembly. But it's not old. We redid the bathroom about 13 years ago and installed it then.
Lately there has been a drip in the cold side. It got horribly worse Friday night. So, naturally, I replaced the washers on both valve stems. This did not help. So then I removed the valve seat.
The surface that contacts the washer looked good but the threads were quite rough on the backside. So I replaced this. It took several tries...1st bare, 2nd putty, 3rd teflon tape. It finally stopped the drip.
Since it was so difficult for what ought to be an easy job, I left the escutcheons off so I could observe.
Now, having just showered I see that, although the valves close adequately, both hot and cold now spew in the wall when opened. I feel certain they did not do this before. There is no sign of water damage that I can see.
What did I do wrong? Are the stems maybe bad? I so don't want to replace the whole assembly. And it really doesn't look like there is any flaw beyond the valves.