Commit is marked as new, despite on it already on branch

Hi.

Here is comparison of two branches. All same commits are marked as '=' But in my situaltion commit is marked as new '>'

Here is my main 'dev' branch
*   8fd53c7d (HEAD -> dev, local/dev) Merge branch 'frontend' into test-dev
|\  
| * 3da9e49c (local/frontend, frontend) 'Save/sync' button is active always
| * d192d9a7 Added library 'materialize' and facelifted the contractor table
|/  
* 0cb280f5 Do not export test data
*   ce1df25f Merge branch 'frontend' into dev
|\  
| * da78b64f Display disabled element title
| * 5f741628 Gen podio ref using document or agreement info
| * 2d756923 Added ref to 'Podio'
| * 129c972d Clean forms when load o reload the page
| * d96c45e4 Use production and test modes in parallel
| * 20bf7186 Added refs to download document and sandbox link for agreement
* | a0e338cb Display only tick for user experience
* | 2b2fb1d5 Merge branch 'frontend' into dev
|\| 
| * d868d72b Added fonts link and some changes for user experience
| * 74426fd0 Added message to say "The docn has been used. Use another docn."
| * b183803b Fill client passport form by parsed passport data
| * b40234ed Fill client form by parsed client data string
|/  
* ed3f3026 Invert data to show provider as 'true' value

Here we see our interesting commit: a0e338cb Display only tick for user experience

Here is branch I do comparison to:
*   ec655271 (HEAD, xtucha/dev) Merge branch 'frontend' into dev
|\  
| * a6085d95 'Save/sync' button is active always
| * bbca694b Added library 'materialize' and facelifted the contractor table
| * 92103b2d Display only tick for user experience
| *   4f0a1881 Merge branch 'frontend' into dev
| |\  
* | | 0cb280f5 Do not export test data
* | |   ce1df25f Merge branch 'frontend' into dev
|\ \ \  
| | |/  
| |/|   
| * | da78b64f Display disabled element title
| * | 5f741628 Gen podio ref using document or agreement info
| * | 2d756923 Added ref to 'Podio'
| * | 129c972d Clean forms when load o reload the page
| * | d96c45e4 Use production and test modes in parallel
| * | 20bf7186 Added refs to download document and sandbox link for agreement
* | | a0e338cb Display only tick for user experience
* | | 2b2fb1d5 Merge branch 'frontend' into dev
|\| | 
| |/  
|/|   
| * d868d72b Added fonts link and some changes for user experience
| * 74426fd0 Added message to say "The docn has been used. Use another docn."
| * b183803b Fill client passport form by parsed passport data
| * b40234ed Fill client form by parsed client data string
|/  
* ed3f3026 Invert data to show provider as 'true' value

$git log --graph --decorate --pretty=oneline --abbrev-commit --cherry-mark --boundary --left-right dev...xtucha/dev
<   8fd53c7d (HEAD -> dev, local/dev) Merge branch 'frontend' into test-dev
|\  
| = 3da9e49c (local/frontend, frontend) 'Save/sync' button is active always
| = d192d9a7 Added library 'materialize' and facelifted the contractor table
|/  
| > ec655271 (xtucha/dev) Merge branch 'frontend' into dev
|/| 
| = a6085d95 'Save/sync' button is active always
| = bbca694b Added library 'materialize' and facelifted the contractor table
| > 92103b2d Display only tick for user experience
| >   4f0a1881 Merge branch 'frontend' into dev
| |\  
| | o da78b64f Display disabled element title
| o ed3f3026 Invert data to show provider as 'true' value
o 0cb280f5 Do not export test data

Here you can see that '92103b2d Display only tick for user experience' commit is marked as new

If I do explicite comarison of a0e338cb and 92103b2d, then we see that is marked as '='

git range-diff a0e338cb...92103b2d -: -------- > 1: 20bf7186 Added refs to download document and sandbox link for agreement -: -------- > 2: d96c45e4 Use production and test modes in parallel -: -------- > 3: 129c972d Clean forms when load o reload the page -: -------- > 4: 2d756923 Added ref to 'Podio' -: -------- > 5: 5f741628 Gen podio ref using document or agreement info -: -------- > 6: da78b64f Display disabled element title 1: a0e338cb = 7: 92103b2d Display only tick for user experience

if I do range-diff between branches dev...xtucha/dev git range-diff 8fd53c7d...ec655271 -: -------- > 1: 92103b2d Display only tick for user experience 1: d192d9a7 = 2: bbca694b Added library 'materialize' and facelifted the contractor tabl 2: 3da9e49c = 3: a6085d95 'Save/sync' button is active always

We again see 'Display only tick for user experience' commit as new

I think problem arise because git does not see that all three commits:
   
| | o da78b64f Display disabled element title
| o ed3f3026 Invert data to show provider as 'true' value
o 0cb280f5 Do not export test data

have same fork-point  "ed3f3026 Invert data to show provider as 'true' value"

Probably because git merge-base get analyzed only left branch and not right: $ git merge-base ec655271 8fd53c7d 0cb280f544113926e1059568811f99c311489d4c

I expect that end of out should look like this:

| |  |
| |  * da78b64f Display disabled element title
| * |   0cb280f5 Do not export test data
| |  |
........
| |  /
---  
|/  
o ed3f3026 Invert data to show provider as 'true' value