Yes bad EU case law that can't be fixed with legislation has been a common complaint of both political parties and independent groups over the years. An example is the Charter of Fundamental Rights which the UK and Poland thought they had negotiated an opt-out of, on the grounds that it was bad law and they didn't want it to apply. The opt-out was negotiated and agreed between all countries and was written in a simple and supposedly "watertight" way. The ECJ simply ignored the agreement and ruled the UK had to obey the Charter anyway.

https://www.politics.co.uk/news/2013/11/13/the-stolen-refere...

It was one of the events that led to the ECJ's perception as an activist court that makes EU law unknowable, because what is or is not illegal can't be understood by reading the treaties or laws. Here's an example of some British lawyers expressing that view:

https://lawyersforbritain.org/wp-content/uploads/2018/04/eu-...

The effects of the Charter, whether applied to UK laws made before or after Brexit, cannot be predicted as its operation would be dependent on the rapidly evolving and expansionist case law of the European Court of Justice, and would open the door to judicial adventurism in our own courts.

Not just the UK has complained about this. Here's an example of corruption in the ECJ uncovered by Irish journalists, in which the ECJ was trying to surreptitiously expand EU powers:

https://euobserver.com/investigations/131569

It is clearly corrupt to hear a bogus case like that where the plaintiff doesn't even know they're in a court case at all and both sides are represented by the same firm, yet nothing was ever done about it.