Why is ember changing the name of my model on the first save() attempt but not subsequent save() attempts?

I have a button that is linked to an action to update then save a model:

// component.js
resolveInvestigation(itemID) {
    let item = this.get('store').peekRecord('customers-investigations-item', itemID)

    set(item, 'status_id', 1)

    item.save()

}
// template.hbs

<button >

The button is part of a bootstrap 'card' style component so there are a few instances of it on the page.

If I click the button on card A I get a console error as follows:

Error: No model was found for 'customers-investigation-item'

I have no idea why it has decided to drop the s from 'investigations' - it doesn't even make the PATCH call. If I then click the button on Card B, the model saves correctly. If I reload the page and click Card B first, I get the error, then if I click Card A, it saves correctly.

I'm at a bit of a loss. I thought it might have been some weirdness with native class syntax or the @action decorator but I reverted to a classic component with no improvement. As an example, I am also saving this model in another part of the app with no issues as follows:

      let items = this.store.peekAll('customers-investigations-item').filter((item) => {
        if (item.isNew) {
          return true
        }
      })
      items.forEach(function (item) {
        if (item.isNew) {
          item.set('customer_id', response.id)
          item.save()
        }
      })

I first thought that it was some strrange plurilize/singularize behaviour occuring on save() but that wouldn't explain why subsequent saves after the initial attempt are fine, or how the model saves in other locations of the application.