Operating system: Windows-10-10.0.18362-SP0 64 Bits
Graphics card: GeForce GTX 1070/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 432.00
Broken: version: 2.82 (sub 7), branch: master, commit date: 2020-02-12 16:20, hash: rB77d23b0bd76f
Also broken 2.83 alpha hash f6d5a9551380
Short description of error
Mipmaps used by Eevee appear to always be generated using tiling border mode, as if texture access mode is just set by modulo coordinates rather than setting the border sampling mode for the hardware.
This is true for both extend and clip modes of texture access.
I can't currently select Cycles rendering engine in 2.82 (presumably a different bug) but the problem doesn't exist in Cycles in 2.83 alpha or in previous versions where I've seen this bug (2.81 and 2.80 if I remember correctly), only in Eevee.
Exact steps for others to reproduce the error
Attached file demonstrates the bug. A plane with a magenta->black gradient texture is set to clip mode. You may need to zoom out to get a visible mipmap demonstrating the problem, as the mipmap chosen should depend on your own personal resolution.
Change to rendered view. At a suitable zoom, a magenta bar is visible on the rightmost margin of the plane.