Question: timelimit has side effects

aa := tan(Pi/11)^2;
bb := RootOf(_Z^5-55*_Z^4+330*_Z^3-462*_Z^2+165*_Z-11, index = 1); # bb = aa
ee := (exp(-Pi-I*Pi*aa/bb))^(1+I);

seq((proc() try timelimit(k, signum(Re(ee)-1/k)) catch: lprint(lastexception) end try end proc)(),
    k = 1..10);

`shake/shake`, "time expired"
`expand/sin`, "time expired"
`evalr/tan`, "time expired"
sdmp:-mul, "time expired"
                        1, 1, 1, 1, 1, 1

An explanation: aa/bb=1, so, as we know from here, ee=exp(-2*Pi), and ee is tricky to evaluate numerically. Normally signum(Re(ee)-1/5) just seems to hang indefinitely, which is not the worst thing it could do. But after one of the timelimit interrupts (or after clicking "Interrupt the current operation"), something breaks, and Maple starts returning wrong values.

This is in Maple 2017.2, system="X86 64 WINDOWS", wordsize=64.

Also, is there any way to clear the cached values so that this computation can be repeated without doing restart?