The screw holding the red conductor was probably only finger tight...or less...or some insulation was under the fastener rather than bare copper.
P7Wang asked "how hot is too hot"... XJ12 mentioned 60*C (140*F). That sounds too hot; perhaps some confusion arises over various conductor temperature ratings - 60,75,90, 105*C all being somewhat common. Those temp limits actually apply to the insulation...they are not design operating temperatures for the circuit.
My imprecise but experienced sense is that "a bit warm to the touch" is OK, but uncomfortably hot is not.
I'm not sure I've come across use of torque tools for electrical connections at the residential / light commercial level, but they do need to be pretty darned tight, and an occasional re tightening of everything in a panel is excellent...and will often reveal some fasteners worryingly loose. My own rule of thumb is that a properly tightened fastener clamping a conductor should cause slight to moderate deformation of the conductor...it "leaves a mark" if you will.
Car charging circuits may be among the higher actual power and longest duration loads in a typical home...30+ amps for hours at a time is not duplicated by many other residential loads, so these need to be treated with respect - installed properly and occasionally inspected.
My monthly driving / charging activity exceeds 1 MWh (a megaWatthour, or 1000 kWh) passing through that one circuit every month...more than the combined total of every other circuit in our all-electric centrally air-conditioned home...that circuit works hard!