I've been told that, when you use a Spell Scroll, there's always a de facto verbal component involved, as you have to read the scroll's contents out loud. That would mean that a Sorcerer using a Subtle Metamagic on a spell scroll would still be counterspellable and couldn't use the scroll in a zone of Silence, for instance.
Is the above true ? (that using a Spell Scroll always include a verbal component)
From the description for Spell Scrolls as they appear in the Dungeon Master's Guide:
A spell scroll bears the words of a single spell, written as a mystical cipher. If the spell is on your class's spell list, you can read the scroll and cast its spell without having to provide any of the spell's components.
And Jeremy Crawford clarified this point in a Sage Advice article:
Spell scrolls follow the normal rule for casting a spell from a magic item: you don't need to provide any components to cast the spell (V, S, or M). Spell scrolls have a twist, though: you must read the scroll to cast its spell. This is effectively an ad hoc component.
So aside from the physical (implied Somatic, depending on whether you need to pull the scroll out of your bag and hold it up or not) component of reading the scroll, no other components are required.
Simply because the action of grabbing a Spell Scroll and reading it will be visible to an enemy spellcaster, they may have the opportunity to attempt to Counterspell it, in a way that a regular Subtle-cast spell would only be Counterspell-able if it has Material Components. This will depend on the exact scenario where the Caster is casting from a scroll; if casting from a scroll that is already sitting in front of them, without clear evidence the caster is reading from it, the spell may not be Counterspell-able.