odd Modulation env. behaviour

I have an instance of Camel Alchemy running and wish to automate the LFO rate via Mod. envelopes. To get the automation lane visible I did the usual thing of setting to write mode and move the said knob. Unfortunately this just makes write mode switch back to read mode and no automation lane appears. Just to check I tried the same process with the filter cut off and it works just fine. I also assigned a midi control knob on my keyboard to the LFO rate and that works, but still refuses to write. I also made sure my midi items were set to items always mix so that will not block incoming midi data. Any idea what is going on here ? Fairly sure LFO rate should be modulate-able since it is assignable to a control knob.

Can confirm, seems rate is not a visible parameter.

This seems to be an Alchemy limitation.