Usually, but definitely not always. Still, if you check the trading during the week prior to ex-div for, say, the past 9 or 10 quarters, you'll see some big sell-offs and some big bouncebacks. Investors buy, investors sell, and traders buy and sell. Recent ostensible "patterns" really just indicate how inexplicable short-term trading can be. Profit-taking? Panic? Folks playing some empirically unproven technical system? Or the directional momentum? Speculation on causes by those who really have no clue? Conspiracy theories based on imagined leaks or insiders buying or selling? Buy/selling based on perceptions of others' perceptions? Maybe sheer dumb luck both good and bad?
The market's a lot more random than we care to think. And I include me in the word "we." But I guess and gamble (and admit it) just as others on this board do but will fess up when I'm wrong, which tends not to be standard on message boards. (As in where's the guy who confidently declared that LINE's going to 40 to 43 in two weeks. Time's up. Guy's gone.) For most people, I believe, stock message boards are driven less by people questing valid information than folks seeking assurance that they haven't made a mistake.
Most boards are loaded with posters who are often wrong but never in doubt. During my working years in another life I used to think of it as the PhD disease. But now I see it as simply a standard flaw in human nature.