What does 1 Chronicles 12:19 mean?

Some men from the tribe of Manasseh also joined David when he was with the Philistines, fighting against Saul. But David and his men didn't actually help the Philistines, because their leaders sent him away, saying, 'He might turn against us and go back to Saul.' 1 Chronicles 12:19 - Modern Text Bible

(Even while David was among the Philistines, people from Israel kept joining him. The Philistine leaders didn't trust David, fearing he might switch sides.)