Fed unreported sub again

[Little Jimmy]

Had this happen in a Fed game today. I was in the field. Home team coach starts a few non starters since their playing a "lesser" team. As things develop and the visitors have a small lead, home coach puts in his top pitcher and shortstop in the field in the top of the 4th. He doesn't report either of them and visiting coach says nothing. The inning goes on uneventfully.

Bottom of 4th comes and unreported shortstop comes to bat. Home team coach tells plate ump about the sub but visiting coach also notices that she was in the field last inning (but says nothing about the pitcher who also was in the field). Unreported sub. Team warning. Inning ends a few batters later.

The next time the home team comes up to bat the unreported sub pitcher comes to bat and the home coach once again gives the substituion to the plate ump. For some reason the visiting coach doesn't say anything about this player already being in the field. Plate ump says nothing. Pitcher strikes out and inning ends. Game ends uneventfully next inning.

Questions. When the pitcher came to bat was she the second unreported sub, meaning restriction to the bench? Was it the visiting coaches responsibility to catch this or was the plate ump obligated to call this on his own if he realized it? After the game, plate ump told me that since the visiting coach didn't say anything then he wasn't calling it. He also said he thought since both players came in unreported at the same time that they were part of the "same unreported situation". I didn't agree but there was no use arguing the point. Opinions?