JM 3.8.1
VM 3.2.4
PHP 5.6.31
'allow_url_fopen' is DISabled

Base currency = GBP

When the plugin is activated, all my activated currencies keep switching to an exchange rate of 1.00

Obviously, only GBP should be 1.00

The same happens if I set the rates to 0.00 (dynamic) or input the current rate.

I have needed to disable your plugin.