[Bug Report][3.7.7] Scroll bouncing virtual table with expanded row

[mpillkann92]

Environment

Vuetify Version: 3.7.7
Vue Version: 3.5.13
Browsers: Chrome 134.0.0.0
OS: Mac OS 10.15.7

Steps to reproduce

The following behavior can be observed:

Structure:
v-data-table-virtual
-> expanded-row ->
v-data-table-virtual
-> expanded-row ->
v-data-table-virtual

Behavior:
While scrolling outside the area of the 3rd table, you jump back again.
The behavior is most likely to be seen when scrolling slowly.

The behavior only occurs when fixed-header = true and the row of the 2nd table is expanded.

Procedure:

1. set fixed header to true via button
2. expand row of table 1
3. expand row of table 2
4. scroll slowly

Translated with DeepL.com (free version)

Expected Behavior

scrolling in multiple nested tables with fixed headers

Actual Behavior

jump when scrolling in nested tables with fixed header

Reproduction Link

https://play.vuetifyjs.com/#...

[J-Sek]

The reproduction is a bit bloated and has multiple unrelated bugs (like missing <tr> around expanded <td>).
It took me a while to observe the problem.

It is quite severe. I cannot scroll down.

Screencast.from.2025-06-24.12-54-53.webm

Simplified playground

• single table, expand row 10, scroll down... bumps me up, same problem