Wrong LCP returned (compared to Chrome performance devtools + grafana)

@connorjclark is already working on this.

Since Nov 23, 2021.

### FAQ

- [X] Yes, my issue is not about [variability](https://github.com/GoogleChrome/lighthouse/blob/master/docs/variability.md) or [throttling](https://github.com/GoogleChrome/lighthouse/blob/master/docs/throttling.md).
- [X] Yes, my issue is not about a specific accessibility audit (file with [axe-core](https://github.com/dequelabs/axe-core) instead).

### URL

https://www.se.com/ww/en/product/LC1D09M7/tesys-deca-contactor---3p(3-no)---ac-3---%3C%3D-440-v-9-a---220-v-ac-coil/?image=opti

### What happened?

- Results coming from performance tab gives an average of **3.2s** for LCP. I set throttling as 1.6Mbit + 150ms ; X4 CPU. [Grafana](https://grafana.com/grafana/dashboards/3837) gives similar results
- Results from lighthouse is somewhere **between 5.5s and 7s** on average ( [lighthouse-metrics.com results](https://lighthouse-metrics.com/checks/7012694d-0932-4e2e-a002-a569fc1d4667) )
- [webPageTest](https://webpagetest.org/result/211123_BiDcF5_acc2d3de27f5a554c51910660da298a6/?view=webvitals) are even better with **2.3s**

### What did you expect?

I was hoping to have something more consistent, at least with Chrome devtools. Something is off with lighthouse results for this page. If the issue is from the page I do not know where to start.
It would be helpful if Lighthouse explicitly names the Largest Content (as we can have in performance tab).

### What have you tried?

_No response_

### How were you running Lighthouse?

PageSpeed Insights, Chrome DevTools

### Lighthouse Version

8.4.0 and 9.0.0

### Chrome Version

96.0.4664.55

### Node Version

_No response_

### OS

Mac

### Relevant log output

_No response_