Auriele

Read the patch notes, multiple zones including Cruma Tower had a change that reduced the amount of items/adena drops but increased the XP/SP gained from monsters.

Cruma Tower was one of the locations that was affected by the update. They changed it so mobs no longer aggro and have increased XP/SP. Unfortunately they also reduced the drop rate of items/adena due to the update. As it stands right now due to the update, thats just how Cruma Tower is now. They changed multiple areas that bots and farmers used. TL;DR - Not broken, read patch notes

Having the same issue on a lvl 26 Palus Knight I made after the update. It works just fine on my lvl 25 Human Wizard though. Have tried using the scroll in combat, out of combat, in a peace zone, restarted client, etc. Edit: Both leveled through the new 1-20 quest system and class changed

Are you not purchasing Soulstone and using the Summon Soulshot skill on your summoner? It is significantly cheaper than going to Giran/Aden and buying Beast SS from the vendor because you can buy Soulstone from any Grocery NPC. It only summons a small amount but it has no CD. Over time it is most cost effective plus Soulstone has no weight, so you can carry tons with you when you go out to exp. It requires 4 Soulstone per cast = 1000 Adena You gain 30 Beast SS per Cast Cost of each Soulshot is then 33.3 adena per, pet beast hit would be 66/67 Adena each hit. It's not a huge chunk but over time it is cheaper. For each Summon Beast Soulshot cast you would be saving 45-60 adena.