I'm glad that solved the problem. It's been my experience that materials within components and especially sub-components will cling on to their former identities with a tenacity that is awesome to behold. Sometimes, not even name changes of material and component are enough.
For instance, here is a file containing a Face Me tree I got from the warehouse. I have edited it. The name of the png, the name of the material and the name of the component are now all 'summer'. The file itself is called tree summer.
I have also attached an edited version of the png in autumnal colours...called fall. Download both, open the skp, then in Materials edit specify the fall image. Also change the name of the Material to fall. Also edit the component properties and change its name to fall. Save the resulting file as tree fall.skp.
You now have summer and autumn versions. Open them each separately and they both look exactly as expected. Now open a new file and import them both. ๐
Of course, you wouldn't normally nest a Face Me this deep, but I'm just using it as an easy example of the problem with sub-components. There is a solution, but you really shouldn't have to take things that far.
tree summer.skp
fall.png