did anyone encounter this weird "bug"

so a day or two ago i sent a vid to my friend and she didnt intialy respopnd, as ussual, but yesterday she said "yoo 1 2 testing testing testing" as seen in the pisture,and she swears that she didnt type it herself i havent ever seen this kind of "bug", for a lack of a better word, before and im really confused on how this could happen,my friend even blocked me because she was freaked out by that,eventualy i contacted her and found out the reson she blocked me. So my question,has anyone ever encountered this weird bug and how can it be explained,because im kinda shocked as well on how this could heppen by it self assuming my freiend didnt type anthing

to be more elaborative,the texts were sent in the moring as seen the screenshot so it wasnt any of her friends just going through here phone,besides it would be weird for somone to go into specifically my dms and type out such a weird and robotic sounding message