About 10 years ago I had a "near miss" regarding rolling over "traditional" and "roth" 401k monies via a "trustee to trustee transfer" into separate, segregated

About 10 years ago I had a "near miss" regarding rolling over "traditional" and "roth" 401k monies via a "trustee to trustee transfer" into separate, segregated accounts on the receiving end. I'm in the US. For whatever reason, and to this day I swear I was not at fault in giving correct or incorrect numbers across the board, both "roth" and "traditional" monies got dumped into the same receiving "traditional" 401k account. Bad times. Fortunately, the person I spoke to over the phone understood the situation ... excused themselves to their manager ... called me back with a solution that included a specialized tax form to sort it all out. A few days later somebody else in the receiving company called me up all "what is going on with this FUBAR?!?". I let them out-wind themselves, then calmly explained the situation as it had been to me, and then all was well for the second time. Tax time came around and thankfully all became well for the third time around. Since I am paranoid against the US IRS, I keep paper records for 9 years and on top of that digital-copy records going as far back as I ever can. Still, this is not as bad as OP-posted article, but I got scared just brushing against such an issue.