No clipboard mgr, and is not file dependent. But I did find a workaround. If I don't forget to switch into Move Tools before copy/paste, it won't crash. But then another issue is that hitting the v key doesn't always reliably switching into the Move Tool (to be clear I am not talking about when you are in text mode).
Say I am doing something like painting, healing brush etc, often I have to hit v key twice, or I have to select different layer in order to switching into Move Tool. Basically Affinity Photo 1.8.3 is less reliable than 1.7 for me. It maybe because my lowly MacPro5,1 16GB is too underpowered? A heavy AF file silently fails to PS color print from this machine but fine from i7 MBP, and this was fine when v1.7 but not anymore.