Flame Wall vs. Solar Orb Ignite Durations

Can someone here explain the difference to me between Solar Orb's guaranteed Ignite and Flame Wall's guaranteed Ignite?

Flame Wall says it "Ignites everything within its area" and that it "Ignites as though dealing X to Y Fire damage.". In the expanded DPS tab, the Ignite Duration is 4 seconds

Solar Orb says that "enemies that are very close to the Orb are Ignited" and the Ignite tab says that the "Ignite radius is 1 meter" and it "Ignites as though dealing X to Y Fire damage.". The Ignite Duration in the Ignite tab is 4 seconds.

Flame Wall's ignite actually lasts 4 seconds, but Solar Orb's ignite goes away as soon as they leave the 1 meter area. Is there a bug with either Flame Wall or Solar Orb or am I not understanding something?


Edit 1: And, in fact, if you ignite them via Flame Wall (or probably any other source--I only tested Flame Wall), then they run through Solar Orb's Ignite radius, it overwrites whatever source was on it previously, puts on Solar Orb's Ignite source, which then proceeds to disappear upon leaving Solar Orb's 1 meter radius, which makes using Solar Orb almost a detriment for Ignite's purposes.

The post powerful ignite will be active. Only one ignite at a time unless an item or passive enables more than one.

I recommend you read this page from PoE1 as a lot of the systems are the same.

https://www.poewiki.net/wiki/Ignite

That explains why Solar Orb's ignite takes priority, but it doesn't explain why it immediately goes away once they leave the 1 meter area instead of persisting for 4 seconds.