UpdateUniforms checked some locations against -1 before queueing the update,
but the GL thread fills them in when it links the program, which can be
later. On drivers that link slowly the check saw -1, the update was dropped
along with its dirty flag, and the uniform stayed unset. On a PowerVR GE8320
and a Mali-G71 the texture clamp values never arrived, so Harvest Moon's and
11655's composites sampled one point of the framebuffer (122k and 76k px off
the Mac's Vulkan render, now 0). The GL thread already skips -1.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>