Actually this issue was several times discussed in this forum in the past.
Like here., here, and here too. There are more though.
The only thing I had changed after realizing this problem was the case. Switching back to the old solved the problem again testing all connectors at hand. Even some users have written their replacement top module did not change this, but results were better without the slim cover.
Depending on if having a 3 pin plug for audio only or a 4 pin plug for a hands-free headset this then makes a difference how the phone will react should the plug not connect properly or slip out a midge while being in use.
There seem to be slight plug tolerances of approx. 0-0,3 mm in lenght depending on the (plug) manufacturer as I could read out of datasheets.