My $0.02 worth.
About four years ago I put a Shorai in a KTM950Adv and inadvertently pinched a wire during install. It was discharged down to low voltage when I tried to start it the next day. This ruined the battery. Shorai graciously offered to replace it under warranty, but couldn't deliver before a planned vacation, so I took a store credit from the vendor and bought an AGM locally.
The Shorai customer service confirmed that the nature of these batteries was that when taken down to low voltages it causes irreparable damage and it cannot be recovered. My Shorai charged back up to voltage, but would no longer hold the voltage over time.
Many people are using these successfully, but in the end there is a price to pay for the weight savings. That price is resiliency against deep discharge. Lead-acid will have a better chance of recovery in this scenario, though they too can be permanently damaged like this as well, often a recharge will result in a working battery. Perhaps with less life overall, but still usable.
I later installed another of this type of battery, from Ballistic, on my DRZ, and it failed early as well. Less than a year lifespan. Though no pinched wires this time, and there are no electronics draining the battery when the key is off.
For my money I will take the weight penalty and simply run an AGM as it offers me a better chance of recovery in these situations and a more dependable lifespan.
I think yours may be toast.
Shorai has excellent customer service and they shoot straight with the customer regarding the limitations, charging differences, and they are generous with their replacement policy in my experience.
The technology is remarkable in how it can deliver greater energy from a smaller package. In the long run I think the application might be better suited to electric vehicles that have circuitry built-in to better control the charge and discharge envelopes to accommodate the battery's unique characteristics.
As a replacement in a standard automobile application there are scenarios that are common enough to damage the battery. It really needs to have a built-in relay that opens when the voltage gets near the danger zone. However, such a circuit would itself require power to operate and would be self-defeating on vehicles left without a tender for any significant length of time.