It is possible one the cam lobes is wearing out.
These cams are critical for oil lube and correct break in.
If you are "racing" get a solid lifter cam.
Less headaches more power and performance.
Use a good oil with zinc and a bit of moly added.
The Shell rotella oil has the good additives to keep the lifters
The GM hyd lifters with the steel foot are the best hyd lifters you can buy.