Can you cite any sources that the above restrictions apply to Bitul Issur l’Chatchila and not solely to the prohibition of creating bread withperceptibleble Milchig flavor.
There aren’t likely any, because whether bittul issur l’chatchila applies here is a machlokes to begin with. So, we’ll go with reasoning.
If it’s assur to be m’vatel milk into bread, it would have the status of not batel, and the same rules would apply as bread with a perceptible milchig flavor.
The Rashba is not relevant here. His limitation is based on its similarity to a Ma’amid, and as we know from YD 87 regarding rennet, Ma’amid is only applicable to Issur and not Milchigs or Fleishigs.
Ah, but you’re once again forgetting that milchig or fleishig bread is not merely milchig or fleishig, it’s assur.
In truth, see the Pischei Teshuva towards the end of YD 134 that the Halacha likely doe snot follow the Rashba.
Then why your comment to yitayningwut?