I have a report I am doing with SSRS 2008 with some rows that have multiple elements inside them. On the preview the row automatically expands to support the extra elements
Came across this (again) recently and thought I'd share my take...
Whether Excel correctly renders the height has to do with merged columns. Take note of your column alignments throughout all objects on the page. Any objects not tied to the data table itself (or embedded inside the data table) must be aligned with the columns of the table in question, at least for the cells that need to wrap text. If there is any overlap causing the table columns to be split and the cells of wrapped text to be re-merged, Excel will not recognize the row height by either setting the CanGrow to True or snapping the row to fit within Excel.
In the original post, the user mentioned rows with multiple elements inside of them. It is possible that those elements caused the column to split for the surrounding subtotals or adjacent groups with wrapped text.
Setting the CanGrow to False will simply prevent any automatic sizing of the row height by default for both the web view and Excel export, so I don't know if that's the ideal solution to this problem.