Dilution is when the OS grows normally. It grew when the dividends were given out, in 2017. That was not dilution because every shareholder got the same percentage of new shares. So, the OS grew, but it was not dilution - EXCEPT for those that bought after ex-dividend date, in June 2017.
Whether the dividend shares are restricted or not makes no difference to the share price. With almost 6 BILLION shares out, most of which are trading, the freed divi shares would make no difference.