Hi folks,

I am having problems getting event detection to work properly in DifferentialEquations.jl. I have reduced the code as far as possible:

```
using DifferentialEquations
using PyPlot
function evaluate!(t, y, δy)
rm = norm(y[1:3])
δy[1:3] = y[4:6]
δy[4:6] = -mu .* y[1:3] ./ rm^3
end
function condition(t, y, integrator)
r = y[1:3]
v = y[4:6]
rm = norm(r)
vm = norm(v)
ecc = norm(((vm^2 - mu/rm)*r - v * (r ⋅ v))/mu)
sma = -mu/(2*(vm^2/2 - mu/rm))
ese = (r ⋅ v) / sqrt(mu * sma)
ece = rm * vm^2 / mu - 1.0
E = atan2(ese, ece)
ano = 2*atan2(sqrt(1 + ecc)*sin(E/2), sqrt(1 - ecc)*cos(E/2))
push!(ts, t)
push!(as, ano)
ano
end
function affect!(integrator)
push!(te, integrator.t)
end
const mu = 398600.4418
ts = Vector()
as = Vector()
te = Vector()
t1 = 5562.095583019713
r = [
6068279.27,
-1692843.94,
-2516619.18,
]/1000
v = [
-660.415582,
5495.938726,
-5303.093233,
]/1000
y0 = [r; v]
prob = ODEProblem(
evaluate!,
y0, (0.0, t1),
callback=ContinuousCallback(condition, affect!),
)
res = solve(prob, Vern9())
idx = sortperm(ts)
t = ts[idx]
ano = as[idx]
plot(t, ano)
for t in te
plot([te, te], [-pi, pi], "r")
end
grid()
```

This is the output:

The blue line is the output of the `condition`

function. I would expect the callback to only be triggered at the upcrossing between 4000 and 5000 seconds. But somehow it also gets triggered at the downcrossing. Am I doing something wrong?