I personally haven’t seen confirmed SEUs in the satellites I’ve designed/operated (as in, an ionized particle affecting a transistor/MOSFET in a way that creates a short circuit and can only be cleared with a power cycle). But it’s good practice to design space systems to have current monitoring and automatically power off in case of such events.

Resets etc. are common, most likely caused by software bugs. This is more or less assumed as a fact of life; software for space applications is often as stateless as possible, and when it’s required you’d implement frequent state checkpoints, redundant data storage, etc. These are all common practices that you’d do anyway, it doesn’t make a huge difference if the software is running on a rad-hard microcontroller or off the shelf Linux processor - although (IMO) there are many benefits to the latter (and some downsides as well.) Assuming a base level of reliability, of course - you don’t want your OBC/PDH to overheat or reboot every 5 minutes.