Most likely a contaminated sample:
https://twitter.com/@twitter/status/1479950248562860038
Click on the link above to read the whole thread.
Added; see also:
Scientists say 'Deltacron is not real' amid claims of new variant
“Deltacron” is probably a lab mistake, not a new variant
Coronavirus: Cyprus’ Deltacron could just be contamination, Imperial College virologist says (Update 2)
Reported ‘deltacron’ likely not actual variant, virologist says/