Are you working with RAW images and then saving as TIFF or PSD? Or are you sending TIFF, PSD or JPG images to PS
If RAW then PS shouldn't be touching the original RAW and no edits you have done in LR should be removed.
Need more info on the type of files you are sending to PS.
It's a bug, and I demoed it to the LR team at Max last week.
A workaround is to to go to the Develop module, open the history panel, and click the top entry in the history panel. All your changes are there, but after returning from PS, LR incorrectly sets the pointer to the original history state.
I am assuming you are working with raw files. When the raw file is sent to Photoshop, the result of the work in Photoshop is saved to a new file that gets returned to Lightroom. The settings that are in that PSD or TIF file are the default settings. However, they include all of the adjustments that were originally made in Lightroom to the raw image. So all of the Photoshop settings as well as the original Lightroom settings become part of the default settings saved by Photoshop. That is why all settings start at the default on a newly saved image from Photoshop.