https://twitter.com/Johnheretohelp/status/1377701619035426818
https://www.theepochtimes.com/walgreens-store-injects-people-with-saline-instead-of-covid-vaccine-company_3781826.html
I find this theory very plausible: In order to keep the public unaware of how toxic the jabs really are the genuine product has been substituted in some cases to limit the number of adverse events occurring at once.