I have MCF7 cell line in culture it was thawed befor two weeks only, and I start to see morphological changes .cells look like fibroblast start to appear as you can see the arrows in the pic below!
i think that your cells are sooo stressed! this cells are slow growth, i recommend you when you dilute it, you pick 1/5 of a 100% of confluence plate to maintenance.
The cells protruded and which reflects stress and the cells may initiate apoptosis. It may be due to the stress upon revival. Just change medium and keep for incubation. Better use 20% FBS to enhance growth of healthy cells. Don't add any mechanical or chemical stress.Dont harvest and seed back. Change media. the healthy cells will multiply
Absolutely no worries! Your cells are good, some elongated cells look like after cytokinesis. Not so good idea to use 20% FCS, keep them at 10% and wait.