Why is the hash not equal when select md5(xml)?

Question

MySQL

Friends, tell me what's the matter, I've already broken my head ...
There are two plates type MyIsam comparison cp_1251_general_ci
and in one and in the other there is an xml field of the longtext type in which there is a large xml. And so here an essence of the task, I want to check on md5 if xml in one plate exchanged - that to update other plates where it yuzatsya. The question is why, with the same xml in both md5 labels, the hash is different when checking?
those. I throw without changes xml from one plate to another i.e. from t2 to t1:

UPDATE `table1` t1
    JOIN `table2` t2 ON t2.id =53
    SET t1.xml_data = t2.xml_data
    WHERE t1.id_t =1999

then I check the hashes using md5:

SELECT 
md5(t1.xml_data) as `md5(t1)`,
md5(t2.xml_data) as `md5(t2)` 
FROM `table1` as t1,`table2` as t2
WHERE  t1.`id_t`=1999 and t2.id=53

but the hashes are different, why so???

Answer 1

show create table t1;
show create table t2;

do they have the same character set and collation ?