My suspicion is that your installation of ATK 12.8 is not able to use your license server because it hasn't been updated to LM-X 4.4, and so each time it needs to check out a trial license, and this is a slow process, really only intended for demo usage.
To solve it, you need to install the LM-X version 4.4.2 server. You can use that with your existing license file, but the server version (3.6.3) used for 12.2 does not support 12.8.
I may be wrong, but this would fit the symptom description. If I'm right, ATK 12.8 will stop working within 14 days of the installation.