I'm about to introduce my new Character into an on going campaign following my previous characters death. I have planned a Wild Magic Barbarian, and shown it to my DM and he questions some phrasing for the Wild Surge feature. Straight from DND Beyond (I don't own Tasha's, just this subclass) it says the following:

Wild Surge

3rd-level Path of Wild Magic feature

The magical energy roiling inside you sometimes erupts from you. When you enter your rage, roll on the Wild Magic table to determine the magical effect produced.

If the effect requires a saving throw, the DC equals 8 + your proficiency bonus + your Constitution modifier.

Now they view the first sentence as the feature doesn't trigger every time you enter a rage. Now I view it as just some flavor text, and follow the next sentence as you roll on the table every time you rage. I can't find any info about a probability for Wild Surge to trigger, or a second dice roll, or anything pointing to it being a chance instead of every time. Anyone have any incite on this as I am a beginner player and this is my first experience with Wild Magic Barb. Thank you in advance.

I think the "sometimes" is meant to refer to the times you rage.

If the effect didn't happen every time you raged (which would make it worse than every other level 3 barbarian subclass ability), it would not say "when you enter your rage roll on the Wild Magic table to determine the magical effect produced."  It would say what causes you to roll on the table first.  As there's no line saying that you choose to activate the wild surge, or you need to make some sort of dice roll to see if it actually happens, it happens with every rage.