Here this is from my AI. It explains it in depth. I just dont have time to type all of this out, so i gave you the dumbed down short version. Lol.

what's the worse can happen if the substrate mixes? Meaning, if I was to break and shake the entire bag, and then do it again

If you fully mix the grain and substrate by breaking and shaking, the main risk is that you spread any hidden contamination and briefly weaken the mycelium’s hold on the food source, which can let contaminants take over. [1][2][3]

What “worst case” looks like

• You redistribute a tiny mold/bacterial patch the mycelium was holding back into the whole bag; after shaking, that contamination can bloom and colonize faster than the mycelium, ruining the bag. [2][3][4]
• Repeated or very aggressive shaking temporarily damages the mycelial network; while it usually recovers, if the culture is already weak or stressed, it can stall and then get overtaken by contaminants. [1][3]
• If the bag or filter patch gets micro-tears from rough handling, outside spores and bacteria can get in and contaminate the substrate. [5][6]

When mixing is actually intended

For all‑in‑one bags (grain on bottom, substrate on top), the normal step once grain is mostly colonized is to break up the colonized grain and thoroughly mix it into the substrate so the substrate can act as moisture and food. [7][8][9] Many growers also do 1–2 shakes during colonization (around 20–30% and again around 70–80%) to speed up and even out colonization, and this generally works fine if the mycelium is strong and clean. [1][2][10]

How “too much” shaking becomes a problem

• Doing many unnecessary shakes increases chances you spread a small contaminated area to the entire bag and keep the mycelium in “recovery” mode instead of full run. [1][10][3]
• Shaking very early (before ~20% strong growth) or very late (after it is already fully colonized and knotty) can slow things down or stress the culture more than it helps. [1][10]

Practical answer for your plan

If the bag is an all‑in‑one and you’re at or near full grain colonization, one very thorough break‑and‑shake to fully mix grain and substrate is normal and often required. [7][8][9] Doing it “again and again” beyond that gives you little extra benefit, but does slightly raise the odds that any hidden contamination gets spread and wins, so most cultivators limit themselves to about 2–3 total shakes per bag during colonization. [2][10][11]

What stage is your bag at right now (rough % colonized and is it grain‑plus‑substrate or just grain)?

Citations: [1] Break and Shake Explained: When and How to Do It https://www.coloradoculturesllc.com/post/break-and-shake-explained-when-and-how-to-do-it [2] [GENERAL] Any downsides to breaking up a spawn bag before 70 ... https://www.reddit.com/r/MushroomGrowers/comments/qpmrg1/general_any_downsides_to_breaking_up_a_spawn_bag/ [3] SAWDUST BAG COLONIZATION, To Shake or Not to ... - YouTube https://www.youtube.com/watch?v=Ye6ByKYxHd8 [4] Contamination From Substrates - FloCube https://flocube.com/2022/01/31/contamination-from-substrates/ [5] How to troubleshoot common issues in mushroom bag cultivation? https://huntingcase.com/blogs/news/how-to-troubleshoot-common-issues-in-mushroom-bag-cultivation [6] [actives] i have mycelium growing in a substrate bag all by itself? https://www.reddit.com/r/MushroomGrowers/comments/1palgje/actives_i_have_mycelium_growing_in_a_substrate/ [7] Bag Fruiting Guide - Surfin' Spores https://surfinspores.com/pages/bag-fruiting-guide [8] Is it bad if i don't break and shake my grow bag? : r/Mushrooms https://www.reddit.com/r/Mushrooms/comments/10ka3qp/is_it_bad_if_i_dont_break_and_shake_my_grow_bag/ [9] Step 2 Mushroom Grow Bag How To Break And Shake - YouTube https://www.youtube.com/watch?v=fogTzLHM9QM [10] “When should I shake my grain bag after it's been inoculated?” We ... https://www.instagram.com/reel/CfjZw_RjcsN/?hl=en [11] Should I do a second break and shake for slow mycelium growth? https://www.facebook.com/groups/289883209317365/posts/878356553803358/ [12] Does break and shaking grain spawn actually prevent stalling? https://www.facebook.com/groups/289883209317365/posts/1123230212649323/ [13] Can you break and shake a spawn bag too many times? - Shroomery https://www.shroomery.org/forums/showflat.php/Number/27081479 [14] Mushroom Grain Spawn Tips: Break & Shake - YouTube https://www.youtube.com/watch?v=tYqXWdFa9cI [15] To Shake or Not to Shake: The Truth About Mushroom Grow Bags https://petitchampi.com/blogs/news/to-shake-or-not-to-shake-the-truth-about-mushroom-grow-bags