LeAnn Rimes' had an intense reaction to having her jaw released in a viral video last week ... but Brandi Glanville isn't thrilled about the clip which she seems to think was oversharing.

Speaking on her 'Unfiltered' podcast, Brandi revealed she knows firsthand how painful deep jaw release therapy can be, as she suffers from TMJ -- a disorder that can cause pain in the jaw. Brandi just doesn't understand the need to broadcast it.

Brandi said, "I just don’t know why you share that ... So weird."

The comment definitely hits a little sharper given their history -- Brandi was famously married to Eddie Cibrian before his alleged affair with LeAnn turned into a full-blown relationship and marriage.

As you know ... Rimes has been openly documenting her health journey lately, and her emotional reaction was deemed normal by expert Garry Lineham.

But apparently in Brandi's world, some things are better left off-camera.