I found on pages 2 and 3 of Martin Haugh's "Risk Measures, Risk Aggregation and Capital Allocation" from 2010 an example showing non sub-additivity of VaR (excerpts given at the end).
I understood the example on the whole, but I would like to clear out this doubt: when we compute the quantile, why for portfolio A we use -5 and l<-5, whereas for portfolio B we use +5 and +4?
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