I am traveling within the US, but my boarding pass shows my first name and middle name joined as such: Firstmiddle instead of First Middle. How do I correct this, or is this something that shouldn't be a problem with identification? I am already on hold with the airline to bring this to their attention, but I am not sure if there's a better way to correct this.
There's nothing to correct. This is very common with airline reservation systems, and everyone handling your boarding pass should know what it means.
Having worked on airline reservations software development teams, PNR name records are usually using antiquated systems and the names are limited to 10 characters for first-middle name. They id you by your drivers license or passport numbers (if that) If you think John Smith is a problem, wait until you see some Asian and pacific islander names, and even middle eastern names... ArtsrunHovhannisyan, VohanHovhannisyan, and a million duplicate Zhang Wei Changs, Wang Fang Chungs, etc. The systems were not designed to handle long names so they are often, very often abbreviated. I.A.T.A. and others have been trying for decades to fix things like this.