plotting – Can you explain strange behaviour of a plot masked with $(2*(-1 + Abs[x]))/(-2 + Abs[Abs[-1 + x] – Abs[1 + x]])$?

I made a code which draws a plot of $5-x^2$ masked with a kind of rectangular function in order to brake the branches of parabola at the points -1 and 1 and transform them into a vertical lines.

Clear("Global`*")
rgbC = RGBColor(0.880722, 0.611041, 0.142051);
pltS = {rgbC};
f = 2 - Abs(Abs(-1 + x) - Abs(1 + x)); 
(*triangular function with height 2 and base 2*)
lin = 2 - 
   Abs(2 x); (*auxiliary function to make rectangular function of 
triangular function*)
k = FullSimplify(
   lin/f); (*rectangular function with height 1 and base 2, defined 
on intervals x(-1,1) and y(1,-(Infinity))*)

eq1 = x^4;
eq2 = 5 - x^2 + k - 1;
fPlt = {Plot(I*x, {x, -2, 2}, AspectRatio -> Automatic, 
   PlotRange -> {{-2, 2}, {0, 
      5}})}; (*empty 'canvas' for applicating combined mPlt and uPlt*)


mPlt = {Plot({eq1}, {x, -3, 3}, Method -> "BoundaryOffset" -> False, 
   AspectRatio -> Automatic, Filling -> Top, 
   FillingStyle -> LightBlue, PlotRange -> {0, 3})};
uPlt = {Plot({eq2}, {x, -1.1, 1.1}, Method -> "BoundaryOffset" -> False, 
    PlotStyle -> {pltS}, PlotRange -> {{-2, 2}, {3, 5}}, 
    Filling -> Bottom, FillingStyle -> LightYellow)};

Show(fPlt, mPlt, uPlt)

The code works as expected when $x$ in uPlt varies from -1.1 to 1.1:

good

But things go curiouser when $x$ is bounded by -1 and 1, the vertical lines desappear:
strange

And it all becomes curiouser and curiouser with $x$ is ranging from -2 to 2, now the only left “leg” is absent. The circumstances are aggravated by the error message ‘infinite expression 1/0 encountered’ popping:
bad
Both legs are gowing back again with {x,-2,3} or {x,-3,3} and the error message persists.
What is going on?