The support team replied with the below. I have just started investigating but the only change between the two js files is to do with analytics but I am trying to figure out what I can do to resolve.
To summarise, you can either disable the js combined optimisation or try to identify the cause and add this to js excludes.
“when certain option is enabled , in this case CSS Combine External and Inline and/or JS Combine External and Inline , the plugin will generate one combined JS file , it will intent to re-use the generated file , but in some case, where plugin or theme will add random string in its code , which makes re-use not possible due to content mismatch
more detail please check this page: https://docs.litespeedtech.com/lscache/lscwp/ts-optimize/#disk-space-filling-fast”