https://www.gatestoneinstitute.org/14910/iran-nuclear-deal-violations
https://honestreporting.com/iran-deal-all-times-iran-violated-nuclear-agreement/
And...from the horse's mouth:
In January 2019, Ali Akbar Salehi, the head of the Atomic Energy Organization of Iran, gave an interview with Iranian state media in which he openly boasted about some of the ways in which Iran had deceived its negotiating partners and the JCPOA’s would-be enforcers in the International Atomic Energy Organization. Salehi described having used decoy tubing and photo manipulation to convince foreign authorities that the core of the Arak heavy water facility had been deactivated in accordance with the deal’s relevant provision. Later in 2019, he added that the AEOI had also established “countermeasures” to avoid being “trapped” by the provisions limiting the country’s levels and quantities of enriched uranium.In June 2017, Reuters confirmed that Iran had exceeded allowable levels of heavy water on at least two occasions before selling the excess for profit. Around the same time, the IAEA’s quarterly report found that the country’s stores of that substance had reached the “very high” level of 128.2 tons. Still, other reports pointed to the country having at least briefly exceeded the limits on its uranium enrichment, but in each case, the agreement’s Western signatories deemed the violations too slight to be worthy of challenge.
