Links posted to forums disappears.

[devoidfeast]

Hello fellows I have vbulletin 5.1.2 installed.when a link is posted to some forum it disappears after some time but when someone reply or like the post the links comes back for example the picture 1 is with the link disappeared and picture 2 is when someone like the post and the link comes back.

i do not know what could the problem be.any help or suggestion will be appreciated.
Thank You.

[devoidfeast]

I have just solve the problem.the solution is go to Admincp>maintenance>Clear System Cache
and everything is good now.