Reproduction steps:
1. Open project attached (FatecSP.Eniac.HortaFeliz.zip).
2. Open scene "Matematica_Tutorial", from "Assets/Cenas/Matematica"
3. Open script "PainelTutorialController" from "Assets/Scripts/Controllers"
4. Add breakpoints at 24 and 25 line.
5. Attach it to Unity and enter play mode.
6. When debugging starts, press F11 few times, once it goes past 26 line.
7. Press continue.

Additional steps.
8. Remove breakpoint from 24 line and repeat steps 6-7.
9. Add breakpoint to 24 and repeat 6-7 steps.
10. Remove breakpoint from 25 line and repeat steps 6-7.
11. Add breakpoint to 25 and repeat 6-7 steps.
12. After doing 8-11 steps for about 3 minutes, restart Unity and try again.

Expected result: Debugger will work fine every time we try to debug.
Actual result: It crashes sometimes. Chance is about 1/20 or 1/30.

Notes: Steps 8-11 are optional and they might not make huge difference.

Reproduced on: 5.5.0f3, 5.6.0f3, 2017.1.0b7.

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Fixed in: 2017.2.0a3, 2017.1.0b9, 5.6.1p3 and 5.5.4p1/2.