That's not supposed to happen
....but it does. The biggest challenge is that on long prints, you aren't there to keep an eye on things when they start to go wrong. This looked like it actually started to go wrong fairly early but after I left.
Cleaning is only a minor inconvenience for the most part. One might think that hardened melted plastic would be a real chose to get rid of. Not so. You simply tell your printed to heat the nozzle to the PLA's melting point and it literally just melts off. Ok, it's not exactly that but once it's to the material's melting point, you can pull it off and wipe it off pretty easily. It's the little nooks and crannies that are likely to give you a bit of a hard time but I think I got most of it, and certainly well enough to continue on printing.
In general, I start a print and wait for the first layer to go down. When that does, then I'm pretty certain the rest will be ok. I didn't wait for the whole layer this time and it was somewhere in that is where the problem began. Luckily this was just a casual print and not for any particular job. Still, it was annoying.
Time to see if it got clogged up inside. That's a bit more work.