It all depends on how an individual uses the vocabulary.
It is logically impossible to have an “invalid Mass” because if it is invalid, it’s not a Mass. It’s like talking about a “vegetarian steak.” If it’s vegetarian, it can’t be a steak. Nevertheless, it’s rather common to find the term used. It’s simply easier than constantly saying or typing “an invalid attempt at Mass.”
Let’s say that the priest has a host (valid and licit matter). The parish is accustomed to using white wine. The priest goes through the offertory with the host. He likewise does the offertory with the wine; or so he thinks. He accidentally uses the water cruet instead and just doesn’t notice. There is no wine in the chalice. He goes through all the parts of the Mass as usual, unaware of the problem. He even drinks from the chalice, but for some reason (maybe he has a bad cold and can’t taste or smell anything) he never notices.
The end result is this:
A valid, but illicit, consecration of the bread into the Body of Christ.
An invalid, and likewise illicit, attempt to consecrate the Precious Blood.
One person might say “this is an invalid attempt at Mass.” And so it is, because for the entire Mass to be valid, both species must be consecrated and consumed. Please take note of the difference between the words “invalid attempt at Mass” and “invalid Mass.”
Another person might say “this is an incomplete Mass.” That person would likewise be correct because only one species was consecrated.
It is possible to have a valid consecration of one species (or even both) outside the context of a complete Mass. Possible, but always absolutely forbidden.
Still, another person might say “this is an invalid Mass.” That person would be using the wrong vocabulary, but still conveying the right idea. In an official church document, or in an academic setting, the proper vocabulary would be required. In an informal setting, people can get away with simply using a shortcut way of speaking and say “invalid Mass” when they really mean “invalid attempt at Mass.”
It’s the same with any other sacrament. In formal language, we NEVER say “an invalid [insert name of sacrament” but always “an invalid attempt at [the sacrament.” Baptism, Confirmation, Ordination, Marriage…all 7 The proper vocabulary is always “invalid attempt at…” But we allow ourselves a certain license in the vocabulary in an informal setting.