No it wasn't, but then again it wasn't an outlier from his recent performances either. It wasn't a case of Pogba playing well against teams that didn't challenge us as much and then suddenly being awful against Spurs, he's simply been bad for coming up to a month in a whole host of different games.
I also don't really agree with your description of Pogba's role over the season as 'deep-lying', it hasn't been. He's had the freedom to get up and down the pitch a lot, and as recently as Friday Mourinho spoke about his expectations for a box-to-box midfielder in reference to Pogba playing in midfield. Sure he's being asked to get back and defend, but he's not playing in a double pivot as a defensive midfielder like people have been saying. The only way you could possibly argue that is relying on the TV graphic at the start of the game and then by steadfastly refusing to let the evidence on the pitch inform your opinion.
As it happens we agree, although for different reasons, about the suitability of that two and Pogba's role in big games, but I simply don't see how the solution to our woes can purely be sacrificing an attacking player to 'allow' Pogba to play an incredibly similar role to the one he has played for most of the season – especially when we played a three at the weekend with Lingard and Pogba playing as deep as each other and Lingard getting through more defensive work than Pogba and nobody noticed – unless you're going to argue that by 'three' you mean Pogba as a 10 and the actual introduction of a double pivot.
In fact let me demonstrate this point properly. Here are four average position charts from our last five games (i.e I've not included the Huddersfield one because Pogba did not start). In none of these does Pogba play in a 'deep lying' position. Matic holds and Pogba has as much freedom as the number 10 (in this case obviously number 14 Lingard) to get forward. In more of these games than others his average position is closer to Lingard than it is to Matic.
The idea that Pogba's playing poorly because he's playing as a defensive player in a midfield two alongside Matic, whether he's supposed to be or not, is just a complete fabrication.
What I find absolutely striking above all else is when you compare the players average positions our formation in real life (i.e. not what some bozzo on at Sky thinks it is) is very close to City's 4-1-4-1 with Fernandinho and Matic taking up similar positions and De Bruyne, Silva, Lingard, and Pogba all doing the same. Obviously taking up similar average positions does not mean players performing identical roles, but perhaps I might suggest that
formations on their own aren't the be all and end all?