Insulated TOP3 triac soldered to Aluminum plate -- will it last?
It's possible that thermal cycling will break the bond, especially if the switching dissipation is high and the frequency is at some optimal spot for fatigue. The triac then overheats and fails 'on' typically.
I don't have a reference for you, but this was a serious failure mode of early SSRs and damaged the reputation of a couple US manufacturers (the SSR supplier and the OEM using them).
That said, this looks fairly decent. SSRs of any manufacture need careful care and feeding to last, especially heat sinking and protection against surges (voltage and current).
Edit: For what it's worth both triac makers ST and WeEn (an NXP China JV) address soldering the tab to the heatsink. WeEn says not to do it. ST says it can be done but they don't qualify their THT parts for that service (so don't do it).

That note is from 2015. It's possible that if they got an order for 100,000 pieces they might bother to qualify their parts for that service.