Invoice paid Mint did not provide a preimage

[whileunless]

Most of the times when I pay with cashu pay I get informed that the mint did not provide a preimage, like so:

Balance: 18629 sat
Pay 5000 sat (5025 sat with potential fees)? [Y/n]: y
Paying Lightning invoice ... Invoice paid Mint did not provide a preimage.
Balance: 13604 sat

only some times the preimage is showed, like so:

Balance: 13604 sat
Pay 5000 sat (5025 sat with potential fees)? [Y/n]: y
Paying Lightning invoice ... Invoice paid (Preimage: **********************************).
Balance: 8596 sat

I use the default mint, i.e. https://8333.space . I was thinking that one explanation of such behaviour is the recipient also using the same mint as me. That, said, it is very unlikely that recipient (a venture business in that case) uses your mint to receive lighthning, or any other ecash mint.

[lollerfirst]

Some Mints use backends which may not provide payment preimages. Do you always NOT get a preimage when paying an invoice with 8333.space?

[whileunless]

Some Mints use backends which may not provide payment preimages. Do you always NOT get a preimage when paying an invoice with 8333.space?

With 8333.space I don't get it 70% of the time.