2009.01.12 10:58 "Re: [Tiff] TIFF standards and technical notes", by Gerben Vos
No, JHOVE doesn't analyze the content, only the tags themselves. So for JHOVE it isn't an issue.
I didn't know JHOVE; Wikipedia says about it:
: Documents are analyzed and checked for being well-formed (consistent: with the basic requirements of the format) and valid (generally: signifying internal consistency)."
I would say that due to the spec's contradiction with basic TIFF rules (e.g., duplicate pointers into data) there is no way you can make a well-formed TIFF when it uses old-style JPEG compression, so I hope JHOVE always marks this as negative for such TIFFs.