Just like if you take out a mortgage on a house and fail to pay the loan back, then the bank owns the house.
In this case since the ISA is used as collateral, the company that originated the loan now owns a lien on the ISA, effectively giving it ownership.
Similar to when you lease a car, there is a company that provides the finances for the lease, and has a lien on the car, which means you do not own it. Otherwise you could lease a car for $250/mo, then sell it the next day for $30k, but you can't because there is a lien on the title.
So in this case, while the loan is outstanding, the originating loan company effectively owns the asset used for collateral. Ownership means you have 100% control over the asset, and in this case, Lambda has given away 100% control over the ISA.
It also means that they are not aligned anymore, since they have received financial compensation for the ISA up front, they can default on their repayment of the loan as it doesn't matter because the collateral aren't shares in their company, but just the ISA itself.