It's possible, but I think the lack of any organized reserve system is the more likely explanation. Kind of like the mistakenly rosy picture painted by Putin's syncophantic advisors who told Putin what they thought he wanted to hear prior to the invasion. The people who knew that things were in such crappy shape wouldn't dare speak up.
So now, Putin was likely told there was a functioning reserve system, so he orders this partial mobilization expecting it wouldn't be tough to pull off, at least administratively. Instead, it's a cluster.
If you are a dictator you should never underestimate how little your toaddies will actually tell you.