The short version is that the mic level control was a bit wonky and the LCD display had developed a thin black line on its right-hand side, and all after only a year and change of moderate (OK, very moderate) use.
I sent the device back to Roland. They very promptly fixed it for a reasonable sum and got it back to me in a more or less timely manner. They also updated its firmware to version 3.02.
Only problem I've noticed after getting it back is that when I made a recording of a jazz band not long ago, the bass was very anemic; no punch at all. I checked the recording on different playback systems and it ain't my imagination. I made another recording and the bass response, both to my ear and via Adobe Audition's analyzer, appears different, i.e. a lot weaker. Not nonexistent, just weaker. The bass-cut switch was set to "off" in both cases.
I've gone back and listened to older recordings made with the unit pre-repair. The bass on a lot of those recordings, whether made with the built-in mics or a Sony ECM 929LT which I've used successfully on other recording projects, is a lot punchier. Audition's analyzer appears to bear my impressions out.
I've notified the guy at Roland whom I dealt with via e-mail. He's on vacation until the 11th.
Has anyone else experienced this issue with firmware version 3.02? Might there be there anything I can do short of sending the darned thing back again? Is there a hidden menu as with earlier firmware versions?