I don't think there's a voice actor who's been around for a while who hasn't received copy from clients/producers that lacks proper punctuation, misspelled words, or awkward phrasing.
It's very frustrating for you, as the voice talent, because your goal is to make your read "sparkle." But that little voice inside your head says "I'm never going to be able to make this sound professional. Just too many errors."
When in a recording session with a client, although tempting, never make fun of or mock the copy. The person directing you may have written it! He or she may not appreciate your on the spot critique. They may think it's a masterpiece.You feel otherwise. Keep it to yourself.
The best thing you can do is to roll with the flow. But you might want to politely say, "Where it says _____, do we want to say_____ ?" Defer to the client. They're paying you. If you're recording from your home studio without direction, you might want to email the client and ask about certain things before you start recording. Sometimes the client is "English second language" and they may be counting on YOU to smooth it out. This is common with overseas companies.
When I lived in Carolina, I use to drive down two times a week to a well known music service company that also produced on hold messages galore. I would sit in a booth for an hour and read message after message as the audio engineer captured my voice over in another room. Almost every session, there was a piece of copy that would come up that looked like no one had bothered to proofread it. More than a few times, I had to bite my lip. (And I have broad lips. Ouch!) Sometimes, the audio engineer would chime in with "Let's try it this way..."
Now, because you've read this post this far, I want to share with you an entertaining, old school recording session with the late, great, actor/producer/director/writer Orson Welles of "Citizen Kane" and "War of the Worlds" fame. He was recording a voice over for frozen peas and burgers, and to say that he was critical of the copy would be a huge understatement. Listen to how his anger builds with every mistake, and then he explodes before walking out of the session. It's a true classic. And funny too! Here's the link.