We run multiple servers hosting hundreds of Laravel apps and recently we noticed that Laravel installations fail at times.
We believe that this is caused by the fact that Laravel recently started using github tokens for downloading libraries. One user can download a limited number of libraries per day with his/her token. That is why the first ~5 installation for a given day go through successfully , whereas all of the following installtions cannot be completed.
I would suggest that you add multiple github tokens which can be rotated at a certain period and this way this inconvenience will be avoided.
For the time being we offer manual installations for those who cannot install it via Softaculous but after all that why we use autoinstallers