Sorting breaks, when sheet is recalculated

A have a workbook, where one sheet is linked to external data (an HTML table from a remote site) – without any local fields – and the other has several columns derived from the first one. Some of the columns are copied verbatim (=Sheet1.A2, =Sheet1.B2), and some contain formulas (such as =A2/B2).

The second sheet is sorted by one of such derived-via-formula columns… For some reason, every time the first sheet is automatically updated (which happens ever few hours), the sorting breaks – and I have to resort it manually.

Is this a bug, or am I doing something wrong?

‘sort’ is not a dynamic property, but does a one time job when triggered, if values are changed lateron a new sort is required,
it’s the same for ‘filter’,
you may also have effects from [tools - options - calc - general - update references when sorting range of cells] stepping in …
if you are tired of the manual rework you might consider automating it by a macro … but that’s ‘not very easy’ …