It hasn’t stained the harder plastic in my shower either. However, it seems to have stained the soft flexible vinyl trim insert that is used to cover screws on exterior joint molding. That soft vinyl below the city water inlet on my TT has a pinkish stain likely from antifreeze released by pushing in on the check valve in the inlet.
2019 Rockwood Signature 8290BS, Reese Revolution pinbox and B&W Patriot 18K hitch
2016 Ford F-250 XLT SuperCrew, 6.2L, 4x4, 6'9" bed, 3.73, w/ snow plow & camper pkgs.
2011 Rockwood Signature 8293SS (2015 - 2018)
2010 Rockwood Roo 23SS (2012 - 2014)