I too doubt the trace amount of residue left after you washed it out was enough to cause anything.
Virus, Viroids, Bacteria, Fungus, Mold, Insects ect, are going to be downfall of Weed, Hops, and Fruit, and Vegetable crops in the future. Its already happening.
Me and another buddy been growing weed since 1972, and never had anything like the purple shit that attacks the growing tips, and works its way all over the plant, and kills it in most cases.
Starting about 10 years ago it started showing up, when in the previous 40 years we really never had any problems. A bit of mold late in the year. Now every year for 10 or more years we lose up to 90% of the crop to some purple plague. And we are in an illegal state, and have to work our asses off to get anything, and we aint young. Especially him. Hes 74. Still diggin hjoloes, and carrying water.
And YES, weve been attacked again this year. Much of it just now starting. Just before, and during preflowering is when it is most likely to start, though I have seen it in early July, but not very many times. 99% of the time with the strains we work with the shit starts in August.
And it never happens to the same strains grown indoors. You can take a nice healthy clone from an inside mother that never turns purple indoors, and take it outside, and it August, the motherfucker turns purple black, and dies.