An element connection can begin to glow if it is overheating. There are a few ways this can happen.
If different materials were used in the element connection ... like if you went to the hardware store and got regular zinc plated washers, bolts, or nuts to replace the high temperature stainless steel hardware, OR if you used hardware store wire terminals instead of factory high temp wire terminals in the connection point.
If the connection point is not tight enough... A loose or even a somewhat snug connection there can overheat from not enough surface area contacting between the parts. Element connection points must be as tight as they can be (without stripping it).
If the element tail is wrapped too many times around the bolt... One wrap only, with no overlap. Snip off the excess element wire. The element tail gets hot too so the more times it wraps around the bolt, the hotter the bolt gets.
You will need to replace the bolt and all the nuts and washers there as well as the electrical wire and wire terminal. Possibly replace the element as well- if it looks bad. Normally the element wire is ok as it can withstand some pretty high temperatures. Check all the other element connections as well.