You may find that while using Gensym versions prior to 2021.1, the g2-text-time-interval-to-unix-time might not treat negative intervals correctly. Instead of applying the minus (-) sign to the whole interval, it applies to just the hours. Consider the following issue;
TXT = "[-8000 as a interval]";
Q = call g2-text-time-interval-to-unix-time (TXT);
TXT: -2 hours, 13 minutes, and 20 seconds
Q: -6400 (expected -8000)
The above-mentioned issue is a known issue in the older versions of G2 and has been resolved in the G2 version 2021.1.
An upgrade to the latest version of Gensym G2 will resolve this issue along with other known issues faced and reported by customers priorly. Therefore it is suggested that you upgrade to the recently available version of G2, i.e. 2021.1.
After you have upgraded to the 2021.1 version, the issue will be resolved.
Note: after you upgrade to a new G2 version, you'll also need to get your license file upgraded.
In the 2021.1 upgrade, the issue will be resolved as can be seen in the following test.