Yes, sorry, this is a known issue related to the fact that Octane doesn't reset the string parameters if the string is empty. The workaround is to write something, any string, in the parameter, for example "clear" ... this will delete the current texture path. Probably something could be done from the plugin side to avoid this issue. I'll think about it.
Computer Graphics Software Developer
Octane plugin development and support: LightWave and Houdini