I have found many abilities that Arcane Surge (AS) is supposed to augment, but does not work as intended. To clarify, these are items that seem to be broken 100% of the time and not random occurrences.
There are instances where the damage from SP bonus does not apply, duration is not extended, and the AoE is not extended. One example would be Abrams' ult.
There are instances where the damage is affected but the duration and AoE are not affected. One example would be Ivy's Stone Form.
Not sure if this is a well-known issue and is actively being worked on or not, but there is a massive list.
There are instances where the damage from SP bonus does not apply, duration is not extended, and the AoE is not extended. One example would be Abrams' ult.
There are instances where the damage is affected but the duration and AoE are not affected. One example would be Ivy's Stone Form.
Not sure if this is a well-known issue and is actively being worked on or not, but there is a massive list.