To follow up my own thread for future reference:
After some inspection I determined the issue to be related to the after market clip. The clip was made by Taurus and was the extended pinky rest variety. At first I swapped out the followers from a Mec Gar clip that worked with the gun. This did not have any effect on the slide lock issue. Therefor the problem must lie within the structural design of the clip. My faith in Taurus has been saved and my little PT111 is working properly again.
On a side note, any one else experience this issue with an aftermarket clip?