With F1 teams having done a lot of pre-event work in the simulator based on information from both Pirelli and the FIA, they were caught out when they arrived at the circuit on Wednesday by the visibly different track surface.
While drivers said it looked like the track had been "painted", it emerged that it was actually a liquid bitumen surface treatment that had been applied last year to help reduce the degradation of the old asphalt.
With the circuit having been used since, elements of this treatment had been worn away on the racing line, which has given the surface a two-tone appearance.
But beyond it looking different, the treatment has impacted grip levels, especially with a contrast between areas where the bitumen remains in place and where it has been worn away.
While the FIA normally informs teams ahead of race weekends of any material changes to the circuit, no notification about this treatment was included in documents that were sent to teams and Pirelli.
Furthermore, Pirelli normally sends engineers in advance of an F1 meeting to deliver up-to-date data on the track conditions, but this was not done this time because the Italian company had none of its F1 personnel free to do it.
It was only when it arrived at the circuit on Wednesday with its engineers that the issue emerged, triggering some surprise.
Asked about how much communication there had been with the FIA about the treatment, F1 chief engineer Simone Berra said: "We didn't get any indication, so we were surprised as well.
"We noticed it on Wednesday when we were doing the usual track inspection, and it was quite clear that this surface was completely different from the old one."
Motorsport.com understands that the lack of warning over the surface was discussed in Friday morning's team managers' meeting with F1 race director Niels Wittich.
Sources suggest that while Wittich admitted to being aware of the work having been done, he did not consider it necessary to inform the teams because it was not a change that should have materially impacted the track's performance level, nor required any change of homologation.
While the grip changes were certainly not extreme enough to have a scenario as bad at Turkey 2020, Berra added that in the future it was clear the circuits should make it more obvious, especially with the FIA, of the impact of any works done at F1 venues.
Asked what had gone wrong with communication over the matter, Berra said: "I think you need to ask the FIA, but it's not a track change that needs re-homologation, or a check by the FIA.
"It was done by Chinese circuit management, and they could have done this without informing anybody.
"But I would say it's not the end of the world in the end because in FP1, let's say, the grip level improved after a few laps, and then the drivers were able to complete the session.
"I think that, for the future, the FIA will try to work a little bit closer with the circuit to understand this kind of information in advance."
The surface treatment issue will disappear for 2025 with Shanghai set to undertake a complete resurfacing this summer prior to next year's race.
