I've recently started updating a driver which was broken by an update a couple months ago, and while log debugging found out that the "<" character seems to truncate the log message as soon as it is encountered.
For example, "command is: <Bedroom Fan;LIGHT;PWR;ON>" is simply logged as "command is: ". As soon as I remove the "<", the log message becomes "command is: Bedroom Fan;LIGHT;PWR;ON>". This is very surprising behavior, and in some cases I can't even control the log so I'm given an incorrectly formatted message out of my control.
For example, the < + b + > turns on bold while the < + /b + > turns off bold. To do what you wish, I would recommend a space between the < and the remainder of the text >.
Ah, wasn't thinking of that, thanks for the tip! This will solve the problem for my custom logs as I can just use < , but this is still going to affect things like stack traces - my specific problem was that it looked like one of my parameters was an empty string, when in fact it was <....>. Hubitat should probably escape characters when logging out exceptions.