ASRS 2118105

I was flying the LPV to Runway 18 on an active IFR flight plan in VMC. At about 1,300 ft. MSL, centered on the glide path, I was issued a low altitude alert, “Check altimeter setting 29.80 etc". I asked the controller what he was showing for my readout and I believe he said 1,200, which by that time was my altitude since I had continued on the approach since all was in order. This is the third time in 6 months this has happened to me at GTU while performing an IFR approach all at proper established altitudes, twice on Runway 18, once on Runway 29, usually passing 500 ft. on descent in VMC. After the first time the aircraft was due a 24-month static altimeter, encoder check. It checked out fine. The Tower Chief is checking into this now. BUT! If this false alert happens in actual IMC on a low approach, it would lead to significant confusion and a safety of flight situation. I do not know if others have had this occur at GTU and I have not had this happen at any other airport.