Renault admits it made too big a change with its Formula 1 engine over the winter, and has paid the price with reliability struggles this season.
Having felt that its power unit had reached the limit of development at the end of last year, Renault embarked on a concept revamp to give itself scope to close in on the benchmark Mercedes and Ferrari engines.
But Renault was troubled by reliability headaches in the early part of the season - which forced it to revert to its 2016 MGU-K - and managing director Cyril Abiteboul said that its ambitions had been too big.
"I cannot look professional if I tell you that these were expected problems, because we don't design a new engine expecting that it's not going to work," Abiteboul told Autosport.
"The reality - and that is still frustrating - is that we are still not great at designing first time.
"Having said that, we've done an awful lot on the engine side - the ICE architecture is completely different, the ERS is completely different.
"We can challenge the decision to do that much in one winter, and frankly, I think we've done a bit too much."
Abiteboul said Renault's reliability issues had been exacerbated by "finger mistakes" while swapping out faulty components.
"When you start having some difficulty with reliability, you do some mix and match in the garage," he said.
"You take an MGU-H from one engine, a turbo from another, an MGU-K from another, and then you start to make a monster!
"That also multiplies the operation and has been very difficult for the engine guys, who also - with all the operations we have done - happen to make some finger mistakes.
"This has made the situation even worse. That's a vicious circle that is very strong and powerful.
"On the chassis side, we [the Renault works team] have also had a couple of reliability issues - the last one being Jo's [Jolyon Palmer] installation lap in Silverstone, which was unrelated to the engine. It was a power assist system, and that's a big frustration.
"I'm putting that down to the fact that it is a team that is young. We have had a lot of turnover in the mechanics, a lot of turnover at the factory.
"People are getting experience and for me lack of quality is lack of experience."
Abiteboul is confident that Renault will be in a better situation at the start of next year.
"It's nearly behind us; it's not behind us yet, but it's a year of consolidation also on the engine side," he added.
"There will be much more stability next year, and we'll be able to focus on extracting more performance from the different components that we have introduced, and hopefully in a much more reliable manner.
"Those decisions are definitely questionable, definitely a great frustration and a big area of disappointment this season."