Who maintains the short stretch of AR 108 in Texas? The pavement doesn't change at the state line, rather it changes at US 59/71. The state line runs just east of US 59/71 parallel to the highway. You can see the Arkansas welcome sign in the background. It doesn't appear that there's a Texas welcome sign.
(https://www.aaroads.com/forum/proxy.php?request=http%3A%2F%2Ffarm3.staticflickr.com%2F2593%2F4220857102_4a9aafe0b8_z.jpg&hash=3e3926cb00cc63035818edcb59d1f79dce7c9a51)
Estimating from topos, the state line is right at the first reassurance marker. I would guess that Arkansas maintains it up to the pavement change; it's probably pretty common for a maintenance change to not be exactly at the border.
If it were VT they would have VT 108 for 50 feet. (VT 26 reference)