Can't disconnect if a lot of traffic
Using Tera Term to help debug serial connection; if the terminal is busy, pressing Alt-I to disconnect does not disconnect until Tera Term can catch its breath.
Set up Tera Term for a com port, 115200 baud; have another device stream constant traffic to it (in my case, a STM32F030 Nucleo board - acts as COM10), say 10 chars per line, as fast as possible.
Hit Alt-I to disconnect. Will not disconnect until the traffic stops (eg, I hit the reset button on the Nucleo board or send new firmware).
v4.93, SVN# 6549