1D ImplictRegion can not be plotted with RegionPlot

I reported this to WRI tech support. This is what I sent them

I have encountered an issue when evaluating an example given in ref/ImplicitRegion. The example before I evaluated its code showed a circle. Evaluation should have redrawn the circle, but it actually produced a blank plot. I enclose a screen capture to illustrate the problem.

screen capture omitted

I believe this example worked in releases prior to 10.4. I would guess the documentation was carried over from an earlier release without having been validated for 10.4. It appears that either recent changes have broken RegionPlot or the documentation was not edited to reflect those recent changes.

This was the answer I received:

I have filed a report with our developers on this issue with the ImplicitRegion documentation. This may allow them to fix the problem in a future version of Mathematica.

Ambiguous isn't it? There is an admission that something needs to be fixed, but nothing that declares the issue to be either a Mathematica code bug or a Documentation Center bug. Perhaps the tech support person didn't know and is leaving it to the determination to the developers. All I really got from tech support was that something is wrong and it might be fixed someday.

Weak as it is, I think it enough to tag the question with bugs.

No, it doesn't. But this workaround helps:

reg = ImplicitRegion[x^2 + y^2 <= 1, {x, y}]
RegionPlot[reg, BoundaryStyle -> Darker, PlotStyle -> White]