You should breakdown your lines of code,
var target1 = Aliases.browser.pageEquipment.FindElement("//se-app/div/div/div/div/div[contains(@class, 'flex-1')]");
var PropArray = ["contentText", "link"];
var ValuesArray = ["a", "b"];
var target2 = target1.FindAll(PropArray, ValuesArray, 15);
for (var i = 0; i < target2.length; i++) {
Log.Message(target2[i].contentText)
}
So it's easier to debug, and check the values.
Check target1 is returning data that you expect, followed by target2.
Also, I'm not sure what 1000 is used for in FindAll? The fourth parameter should take a Boolean value.