Great! I thought it was just me and my old computer!! I have been having the same exact problem! Hack: type one character, move the cursor in front of that character and type normally. Then just erase that character when you are done typing. It seems the space bar works fine putting spaces in front of something, but not after the last character in a PM.
well i hit the space bar harder thinking it was dirty or stuck got no where so went and used dashes i am not as high tech as you are, bigger hammer kind of guy sometimes maybe thats why i dont make purty stuff like you do rennie
For what its worth I was seeing that behavior yesteday, but just updated chrome to the latest version this morning and haven't seen the issue as of yet.
I have found some information on it on the web. It's a little complicated, but apparently it's limited to chrome and has to do with the version of the editor that VBulletin 4 uses. It does not look like there is any kind of fix available with regards to updating Vbulletin, as it has to do with the way chrome and the editor work together.
Some folks seem to claim that Version 54.0.2840.87 m of chrome fixes it, other folks seem to see the same issue.
Supposedly pressing enter before you start replying helps.
When I had the issue, I would just type a character, then move to the left and type as normal.