Your first sentence does not make much sense to me. If somebody leaves your company for any reason, they should get to keep everything they earned to date.
I’m not familiar with Irish pensions, but in general if the benefit has a vesting schedule that means you earn it over time.
If you leave the company for any reason you get to keep the part that’s vested, and not the remaining unvested part.
> The pension clawbacks, which are legally permitted under Irish pension rules, only applied to staff who had been working with the company for less than two years.