I'm not sure we're talking about the same thing. I was talking about Iran backing Hezbollah and other anti-Israeli factions, which I'm pretty sure they didn't exactly make a secret of. The JCPOA was very much lacking in restrictions in that department, because ultimately, it's a local problem that the global powers didn't care too much about. This was definitely a flaw in an otherwise good deal.
You mention compliance, so I assume you mean Israel's claim about the "secret" nuclear program? Yes, that one was a very transparent lie. Iran had very good reasons to comply and get the great powers off its case. They'd have been very stupid to risk throwing away diplomatic credibility by randomly breaking deals, even unofficial ones. They wanted the sanctions gone, after all, which is why they were absolutely transparent about their compliance.
The alleged "secret" program had stopped in 2009 and been covered in the IAEA report. The director of the IAEA even said as much when Israel made that claim. They straight up fabricated a nuclear threat that wasn't there to goad the US (well, Trump really) into supporting their genocidal ambitions. That is absolutely evil.