Apps in background are crashing
I get this on MotoG 4.4.2 as well. It appears the MotoG has a very aggressive application culling in general. This link explains what the XDA group does about the problem.

In short, there is a 'minFree' system configuration file (sys/module/lowmemorykiller/minfree) which the OS uses to try and keep some minimum amount of memory free. Unfortunately, in stock MotoG 4.4.2 the setting is very aggressive and basically means only one application will be kept around (depending on memory footprint). In 4.4.4, this minimum amount is relaxed.

With rooting you can adjust the setting; or upgrade to 4.4.4. There's a helper app, MinFreeManager (requires root access), which can help adjust this settings file as well.