As Tom Givens has said so well UCR data is voluntary - not all agencies submit data and the quality of the data varies wildly.
Garbage in/Garbage out.
Politics often plays a role. Agencies under reporting the severity of crimes to make their stats look better. The wish.com Glock plates have caused a real increase in illegal full autos on the streets but I also would not be surprised to see politics driving sone agencies to misreport “automatic weapons” to support a gun control narrative.
Automatic weapons does not necessarily mean NFA registered legal automatic weapons. In addition to the wish.com Glock plates there has been an increase in 3D printed auto Sears (aka “wall hangers”) among sone extremist groups.
The shooter from the Oakland federal court house shooting who subsequently ambushed Santa Cruz Sherriff deputies this year used a suppressed 80% 9mm AR which, if I am remembering correctly, was also full auto.