HD radio errors: WPGC 95.5 IBOC callsign changes to “HD-FM” on radio screen

UPDATED 6/9/12: WPGC has since restored their callsign to “WPGC-FM” on the screen as seen before.

While DXing an E-skip opening into the midwest tonight, I noticed local 95.5 WPGC Morningside, MD, 23 miles, reverted to “HD-FM” as its callsign as seen below on the Sony XDR-F1HD radio:

(incorrect) (correct)

I believe the “HD-FM” display could be a default which appears if the station either doesn’t set up a text ID in their IBOC system, or an error causes the correct calls to be replaced by the generic ID.  The only other time I’ve seen this was with the decode of 106.5 WSFL New Bern, NC in 2011:

It is unclear if WSFL’s current display reads “WSFL-FM 106.5 MHz” as I do not regularly receive the station.

This isn’t the first time an HD radio callsign changed locally in Washington, DC in error.  On April 8, 2009, the callsign for local 93.9 WKYS Washington, DC changed to KHRS-FM, as seen below:

To further the mystery, a fellow DXer in Texas sent in a screenshot of an unidentified 97.5 FM IBOC decoded with KHRS-FM, too a few years ago:

Screenshots from all stations above have been added to the Woodbridge, VA FM Screenshots page.