It seems quite amazing to me that in this day, with alllll of the experience there must be designing and building this kind of equipment, there are still stupid issues and bugs.
That's just it. There isn't a lot of experience in these areas. The equipment is extremely expensive, so it doesn't find it's way into so many installs. And where it does land, it's installed in a very precise manner, specific to that one job. If you're the traveling engineer, it's unlikely you'll see the same installation twice. (unless you're working at the same company/site again.) And if it's like all the toys I've worked with over the years, you aren't working with them constantly and forget all the finer details of how to work with them.
It's not like Cisco IOS... been around almost unchanged for 20 years. It's found on an unimaginable number of devices that millions of people have used, openly documented, and continue to touch on a daily basis. When you have a problem, one of the first 3 google results for the error message you've gotten will have the solution.