1. The most probably, this RVF was saved without TextStyles and ParaStyles.
So, when loading in TRichView linked to RVStyle with the same items in TextStyles and ParaStyles, it looks like the original document. Otherwise, styles will be mismatched, and text styles linked to non-existing (with too large indexes) TextStyles will be displayed as white-on-red.
Solution: make sure that the editor saving RVF has rvfoSaveTextStyles and rvfoSaveParaStyles included in RVFOptions.
(in the editor that loads the file, must be RVFTextStylesReadMode = RVFParaStylesReadMode = rvf_sInsertMerge, but it is the default value).
2. Another possible reason: this editor is linked to the same TRVStyle component as another editor. When this another editor loads another RVF file, it loads TextStyles and ParaStyles from this another RVF file, and styles in all other editors linked to this TRVStyle become mismatched.
Solution: use its own TRVStyle component for each editor.
I recommend using the same RVStyle for several editors only if you have a fixed set of styles, i.e. they are not added and not deleted.
In this mode, you can have a single TRVStyle in your project, and assign RVFTextStylesReadMode = RVFParaStylesReadMode = rvf_sIgnore for all trichviews.