After introducing a raft of upgrades in Monaco, Mercedes seemed to be on an upward trajectory with a double podium in the Spanish Grand Prix and another podium place for Hamilton in Canada.
But two weeks on Mercedes took an alarming step back in Austria, with Hamilton and team-mate George Russell finishing eighth and seventh respectively.
Hamilton said the Brackley team's Red Bull Ring woes were "definitely surprising" after its recent resurgence as his W14 felt worse to drive than in the previous two rounds.
"I definitely didn't expect to be as bad as we were today," he said.
"I don't really have an answer for it, really. It's definitely surprising but the feeling of the car was very much the same as the feeling I've had all last year, so in that respect it's not the biggest surprise.
"[The car] was definitely different compared to the last two races. The last two races were way, way better than today."
Hamilton's handling problems were compounded by overdoing a front wing tweak to stabilise the rear end of the car.
In doing so he said he struggled to stay on the track in Turns 9 and 10, incurring a five-second track limits penalty after only 17 of 71 laps.
After the race he was one of several drivers to be penalised a second time, with a 10-second penalty which dropped him behind Russell in eighth.
"We knew that we had really bad rear end here, so we took out a lot of front wing to try and keep that balance so that we could do a long run and go long.
"And we massively overdid it and I was almost full lock around the last two corners. Going into Turn 10 I was just sliding, and I couldn't do anything about it.
"So through the stops we then added a lot of wing and the car started to slowly come back to at least getting round and staying on track."
Hamilton may have been the first, but far from the last driver to be handed a track limit penalty as the FIA couldn't keep up with a flood of 1,200 potential transgressions in the final sector.
The issue also led to a protest by Aston Martin against the race result, which was heavily revised over four hours after the flag.
"I think they need to probably find a new solution for this track," Hamilton thought.
"Years ago, when we didn't have the track limit thing the track was much more enjoyable to drive."
"It's strange to be driving and to have to almost comment on the car ahead, because that's what the team wants you to do.
"But that's not motorsport and not racing, you know?
"[Lando Norris] was going off so much, it was insane. As soon as he passed me, he went off like at least 10 times and so did [Sergio] Perez.
"Obviously they should just be able to go off and none of us get it."