SUMMARY
With kio-gopher 0.1.99, Veronica2:
gopher://gopher.floodgap.com/1/v2
does not work as expected, because the question mark separator in the URLs gets swallowed somewhere in the stack. This may well be a bug somewhere lower in the stack, but for now I am blaming kio-gopher.

STEPS TO REPRODUCE
1. Start Falkon ≥ 3.1.0 with the KDE Frameworks Integration extension, or Konqueror with KHTML (or a recent enough Konqueror+KWebEnginePart, but the version of Konqueror I have installed is too old, so I was not able to try that, whereas I was able to reproduce the bug both with Falkon and with Konqueror+KHTML).
2. View gopher://gopher.floodgap.com/1/v2
3. Click on any search link, e.g. gopher://gopher.floodgap.com/1/world/search-hosts?com%20net%20info%20land%20org (or use the search form gopher://gopher.floodgap.com/7/v2/vs )

OBSERVED RESULT
'/world/search-hostscom net info land org' doesn't exist!
Manually escaping the question mark, as in:
gopher://gopher.floodgap.com/1/world/search-hosts%3Fcom%20net%20info%20land%20org
brings up the expected result.

EXPECTED RESULT
The links on Veronica2 should work without manually escaping a character.

SOFTWARE/OS VERSIONS
Fedora 28 with updates
Falkon 3.1.0
Konqueror 18.08.3
KDE Plasma 5.13.5
KDE Frameworks 5.55.0
QtWebEngine 5.12.2
Qt (QtBase etc.) 5.11.3
kio-gopher 0.1.99