For various reasons, node tools don't support some data. Shape keys aren't supported because their format is entirely different for evaluated and original data-blocks, and node tools currently work in the "evaluated" world. Though that would be nice to change, in the meantime users should at least be warned when this happens. This PR adds a simple "Mesh shape key data removed" operator warning. See #113662 Pull Request: https://projects.blender.org/blender/blender/pulls/118986