Working over the weekend it seems that pac pcf push --force is currently broken once a PCF component has been loaded into the environment.
It works when the component is first installed but all subsequent attempts fail to update the component even though --force confirms it is successfully).
I don't know if it's relevant but running pac pcf push without the force option results in the following error message (which I think is different to before so I suspect might be related).
Checking if the control 'hdn_hdn.DynamicOptionSet' already exists in the current org.
The control exists in the current org, loading the control's details.
Comparing the manifest in the current org to the manifest at \DynamicOptionSet\ControlManifest.xml.
The control manifests are the same.
Using incremental update.
Locating the web resources used by the 'hdn_hdn.DynamicOptionSet' control.
Error: Unable to cast object of type 'System.String' to type 'System.Byte[]'.
Thanks,
Ben