[Bug]: Tarantula doesn't work in flipped sectors

[weluvgoatz]

SuperTux Version

Latest Nightly

System Information

Windows 10 64 bit

Expected Behavior

The spidermite and tarantula should descend normally in flipped sectors.

Actual Behavior

Instead, they shift up weirdly, and then shift back down, and then when they descend, their web is not attached to where it should be.

Steps To Reproduce Actual Behavior

Make a level and add some tarantulas. Flip the level by any means, and provoke the tarantulas. You will see the problem.

Additional Information

No response

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• I have verified this isn't an issue that's already been reported.
• I have verified this isn't a discussion, or an issue about a crash or a feature request, but rather an actual bug ─ that is, the game did something not intended.
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• In this report, I have only included details about one (1) bug.
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