The liquid-rescale plugin goes back to Gimp 2.6 (and earlier) If you got it from http://liquidrescale.wikidot.com then you need a more recent compilation.
samj compiled a 64 bit version, zip file attached. Remove whatever you have installed.
Unzip gimp-lqr-plugin.zip and put the whole folder gimp-lqr-plugin in your Gimp 2.10 profile plug-ins folder C:\Users\"yourname"\AppData\Roaming\GIMP\2.10\plug-ins Like this: https://i.imgur.com/jyMB9VB.jpg
In Gimp 2.10.12 / Win10 64 bit: https://i.imgur.com/TqfULy7.jpg
samj compiled a 64 bit version, zip file attached. Remove whatever you have installed.
Unzip gimp-lqr-plugin.zip and put the whole folder gimp-lqr-plugin in your Gimp 2.10 profile plug-ins folder C:\Users\"yourname"\AppData\Roaming\GIMP\2.10\plug-ins Like this: https://i.imgur.com/jyMB9VB.jpg
In Gimp 2.10.12 / Win10 64 bit: https://i.imgur.com/TqfULy7.jpg