Operating system: Windows-7-6.1.7601-SP1 64 Bits
Graphics card: GeForce GTX 660 Ti/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 445.87
Broken: version: 2.91.0 Alpha, branch: master, commit date: 2020-10-11 22:38, hash: rBdf3d124e9104
Default Merge distance in Array modifier is 0.1 meter now. It is mistake, obviously (too large and requires editing almost always).
Short description of error