The following lines look like an attempt to have the WEB2PY_MIN branch execute by default:

This Bash syntax is a string comparison, so "1" won't be equal to "true". Looking at other usages of WEB2PY_MIN, this is the only instance where it is set to a number, so the simplest would be to change to ENV WEB2PY_MIN=true.

Alternatively, if a numeric flag is preferred, you could use the following Bash syntax:
if (( WEB2PY_MIN )); then

You would also need to change all instances of this variable to 0 or 1.

Background: https://mywiki.wooledge.org/BashSheet#Testing