Hello Victor
Please have a check in the following SAP KBA which explains about the symptom described by you in this thread:
2030570 - UWL task appearing as text instead of hyperlink
By the way, this and many other UWL KBAs are grouped by category at:
The only curious thing regarding your scenario is that according to what you've mentioned, if you clear the UWL cache the problem is resolved. BUT after some time, problem reappears. That's strange and shouldn't be the case.
Please verify according to the KBA.
Regards,
Armando Zaro