There is a strange bug when it comes to Spanish provinces.
As second level geographical units in Spain PGC uses the Comunidades autónomas. As third level units the provinces.
Thus, there is a second level unit "Comunidad de Madrid", which is fine. However, this contains two third level units, namely "Comunidad de Madrid" and "Segovia". There is the bug. Firstly, the province of Segovia is part of the Comunidad autónoma de Castilla y León (and is also correctly enumerated there as well). It should, therefore, not appear as subunit of "Comunidad de Madrid". Secondly, the "Comunidad de Madrid" in reality contains only one third level unit = province, and this should be called simply "Madrid".
This problem is consistently present within PGC, whether it is geographical filtering or the maps in the statistics, which for "Comunidad de Madrid" also show next to the province of Madrid also the province of Segovia not belonging here.