Grassley does this periodically. Not sure why but the textspeak is not new.
I have no sauce but I would look to his social media person being a millenial texter - from the days of flip phones and small twitter character limits
Working in social media - I can tell you that when Twitter expanded to 280 characters, plus links and pictures - more serial twats started to appear.
a few years ago - people didn't even bother.
IMO only